Welcome to the RTA Forum!

I agree with Donna about your plans for your drive down, and actually, I think you're really pushing it to try to drive back in 2 days as well. To get from Vegas to Boise via US-93 is about 630 miles. That's a long day on the road on the freeway, and you'll be on slower going 2 lane roads for most of the day. I can assure you it will take you far more than 10 hours. Its going to be a good 12-13 hours on the road, minimum. I-15 is about 100 miles longer, but the drive times will end up being fairly close because you can go faster, and stop less often on the freeway. Anyway you look at it, it really is too far to drive in one day, and expect to still have the energy another 11+ hours to Vancouver the following day.

There is no place anywhere in the US where you'd be 300 miles between gas stations, and that's certainly not the case around Yakima, which is right along an Interstate highway. Having said that, US-93 is one of the most empty highways in the US, and that is a road where you will go long distances between opportunities to fill your tank. You should plan to fill up as you leave Vegas and make sure to fill up again in Ely, as you'll have very limited other options until you get to I-80 at Wells, NV.