The season, the route, maps, GPS, choice of vehicle
Hello MikeN,
If the winter of 2012 is an average one, you'll surely see enough of cold weather and snow to estimate your tolerance for it in Idaho and Montana! Here are some additional thoughts and ideas:
Forget tent camping. The chance of finding a campground open and a campsite cleared of snow is close to zero. I think you mentioned a tent in the original post as a part of a "survival kit" as opposed to a source of regular overnight sleeping accomodations. While I'd certainly take a below-zero (F) rated sleeping bag for each person, I wouldn't bother with a tent. With the exception of the Sun Valley, ID area, and to a small extent the Bozeman, MT area, the places you're tracking aren't heavily traveled by we skiers, so I wouldn't generally expect motel rooms to be booked up.
In further discussion of the route(s), I'd make myself aware of the elevations in general and the locations of the passes by some map study ahead of time (see below for map suggestions). While the lower elevations see their share of cold weather and snow, it's the higher elevations which get the greatest amounts of snowfall. More on point, where the various highways traverse mountain ranges in between valleys, snow and ice accumulation is greatest and the removal and navigation challenges the greatest.
If I were wanting a really close look at ID and MT and was to spend nearly a month exploring, I'd absolutely have a copy of the Benchmark Recreation and Road Atlas for each state. At approximately 1:250,000 scale (about 1" = 4 miles) the map books provide great detail as to topographic features (but are not topo maps as such, rather they are shaded relief with many elevations included for peaks, passes, crossroads, etc), and are great for navigating the named states. I nearly wore out my ID and MT Benchmarks in July 2010 and 2011, and ditto my Wyoming and Utah Benchmarks in January 2011, just by keeping them on the truck dashboard and thumbing through them many times each morning, noon, and night. The Benchmarks show all of the passes, with elevations included, and that's most helpful in my opinion. I'll readily acknowledge the Rand McNally maps do a good job of showing passes, but in somewhat less detail.
For use as PURELY a secondary or tertiary navigation tool, sure, bring the GPS. Just don't rely on it to find viable alternative routes through the mountains, as did the Chretiens in the post I originated in May of this year. "Death by GPS" is real.
I will respectfully disagree with AZBuck as to choice of vehicle, not because I think a 4WD or All Wheel Drive (AWD) is a requirement, but instead due to possible restrictions as to use of chains on a rental vehicle and the possibility that either chains or 4WD/AWD will be a requirement, of a temporary nature, as you traverse the passes. In addition, the small 4WD or AWD SUVs are ubiquitous at rental agencies. A small SUV will be in a station wagon configuration, too, and most have rear seats which fold down flat, possibly creating enough room for deploying those sleeping bags in a pinch. The Western states have various "chain laws" which are triggered by local conditions and require either chains or 4WD/AWD during periods of severe weather. It's unlikely to see "chain laws" affecting a given pass or stretch of highway for more than a few hours to half a day at any given time. The highways out there, particularly the Interstates, are the economic lifeblood of the region, and enormous efforts are directed to keeping them open to all traffic. A severe event might keep certain passes closed for a few hours to half a day or so, but longer closures are uncommon to rare. That leads to a final comment about emergency supplies: Yes, keep some water and food on board, with winter clothing, hats, gloves, and warm boots/socks. The chance of needing them due to being stranded is quite remote along your route, but to get out and enjoy the countryside in winter will require them, anyway. In the unlikely event you become marooned, it will likely be due to having wholly ignored fair warning as to a day's weather forecast, very poor luck, or some combination of the two.
Last comment (I promise!): For a month's travel in winter, be sure to purchase a gallon of windshield de-icing fluid. Keeping the vehicle's windshield-cleaning reservoir full of this fluid will enable you to regularly spray the windshield with a cleaning fluid which won't freeze, and your wipers will distribute the solvent to keep the salt spray and general grunge from melting snow and ice clear of your view. Most rental vehicles I've picked up in Salt Lake City or Denver have a nice long-handled ice scraper/snow brush on board. If yours doesn't, I'd get one at the same Wal-Mart where I acquired the extra de-icing solvent.
Have a great time planning and taking your Winter RoadTrip!
Foy
Always happy to see folks considering living in one of my favorite places, but.......
.......you must promise not to tell anybody how nice Montana is!
I'm somewhat of a digital illiterate and spend little time trying to rectify the situation, but I believe you can link to map book sellers such as Amazon right here through RTA. I further recall you can have a zoomed-in look at Benchmark map pages on Amazon's site. I was trained on USGS 1:24,000 scale topographic maps so I have a strong affinity to topos, but I have embraced the Benchmark shaded relief maps of the Western US states and now very much prefer them to the topographic DeLorme Atlas and Gazetteer series. While the DeLormes are of similar scale to the Benchmarks and are topo based, the contour lines are fairly faint and the contour interval can be curiously poorly selected, combining for little use in my personal view. The shaded relief Benchmarks, by contrast, depict the higher elevations in white, with darkening shades of tan as you drop into the valleys. Many topographic features have the elevation, in feet above sea level, printed beside them, and in particular peaks in a mountain range, highway-traversed passes, lakes/reservoirs, towns/cities, and even major highway intersections have elevations displayed.
I wouldn't say the small SUV is the predominant vehicle offered at Western airports, but there is normally a wide selection of them. You might want to look into booking sooner rather than later, as in the higher-traffic airports close to skiing the SUVs do get booked up. You might also look into "off airport" rentals, where the rates are often rather less, in part because on-airport agencies have another tier of taxes and fees levied by the transport authorities and local governments. Lastly, I've enjoyed some success with the "Rent a Wreck" franchise and am disappointed that they closed their Salt Lake City facility. A weekly rate on a Rent a Wreck SUV was less than half the price of a brand-new SUV in recent years. Yes, the last one I rented had 120,000 miles on it and the "check engine light" was blinking from the time I picked it up until I dropped it off, but the locals assured me it was merely an automatic reminder that the oxygen sensor was due for a change, and the vehicle ran like a top the whole week.
Have a great time, and remember to keep the secret about MT and ID.
Foy