Hello all!

So at the end of May I'll be embarking on my first big road trip. We'll be starting in Vancouver, BC. Through Portland OR, Weed CA, San Fran CA, Bakersfield CA then Vegas NV. On the way back up I'll be doing the drive by myself, so a straight shoot from Vegas to Boise, ID, then back home to Vancouver. The places in bold are overnight stops. So I have a few questions but I'll just quickly lay out our estimated itinerary.

May 27 - Van - Portland (stopover at the incredible Powell's bookstore)
- Portland to Weed (staying overnight)
May 28 - Weed to Sa Francisco (stopping for lunch, a little looking around)
- San Fran - Bakersfield (Staying overnight)
May 29 - Bakersfield - Vegas (Staying 3 nights)

June 1 - Vegas - Boise (staying overnight)
June 2 - Boise to HOME!

So questions
1) Taking this route down we will go through the Cascade Mountains and even though it's late May I have heard of there being random snowstorms through there. I will obviously keep an eye on the weather as it gets closer to our departure date but just wondering if anyone had any experience?
2) On my way back I was hoping to take the 93 all the way from Vegas to Boise as opposed to the 15. What are the advantages/ disadvantages? I had heard that there's a stretch around Yakima that is over 300MI without a gas station. My tank holds about 600-700km worth but I'd rather know going in when the last place I can get gas would be.

The trip to Vegas itself is on par with the road trip part of our excitement; we want to see a little on the way down but are only planning the few stops to break up driving intervals (I drive stick, my friend does not, therefor I'll be doing all the driving) Is there anything else I should be aware of? This will be my first huge road trip, first time doing one through the states (I'm an Aussie national with Canadian PR) I'm excited but very aware that it's a long trip, especially my drudge home doing two 10 hr days.

I am a member of an immigration forum that helped me get PR so I'm a huge fan of all things forums. They are the most underrated sources of information on the internet!

Thanks guys!