TIPS FOR DRIVERS - Courtesy of 107ist member Paul Schmidt
Since I have a whole reputation tied up in drives from Boise to both cities, I owe some guidance to those of you making your first trip on this route.
The time I went straight through, I did it in 11.5 hours (but, of course, it registers as 12.5 because you lose an hour before entering Idaho). I wasn’t exactly legal that day, but it was the early 90s; speed limit was a straight 65. Aside from gas savings and environmental concerns, you’ll be happy the limit in Idaho and Utah is 75. You don’t have to trust me… you’ll see soon enough.
About I-84: it’s not driving north or south on I-5. There are greater distances between towns, a lot more desert; spontaneity is not generally rewarded. You pay a serious premium for gassing up in towns smaller than Pendleton. I don’t envy vegans making this drive; you will find that most of this route worships the burger. (Boise does have an option or two, but I have to track the name changes again before I can declare anything, but if you can handle Subway, there are enough of those along the freeway to manage.)
I might suggest breaking up this trip. There are some half-decent places to stay in Pendleton, La Grande, Baker, and maybe Ontario for under $50, and there are a couple decent places to stay for more if you wish. Yeah, expect Motel 6 or so if you pay less. Departing from Portland around evening rush hour, you should expect to reach Pendleton in 4 hours, La Grande in 5 and Baker City in 6. I am factoring in stops. I’ve usually done it in less, but that’s out the window when you’re sharing rides.
Driving east provides some early issues. The curves and the wind in the gorge will slow you down a bit, if only because it slows the rest of traffic. Climbing Cabbage Hill out of Pendleton strains any vehicle. Climbing into Ladd Canyon out of La Grande is a bit stressful to the car. Don’t be dismayed if you make a stop in The Dalles; you might need the break. If you can hold on another 20 minutes, however, you’ll find the truck stops and C-Stores in Biggs to be plentiful and easy to work through. I really think stops in Biggs, Pendleton, and Baker City (for those driving through) are timed about right. Once you pass Baker City, while there are more curves to deal with between there and Ontario, the drive is less stressful, and you’ll get used to the rhythm of this drive.
If you split up the trip – I haven’t found too many places other than the faster foods in Pendleton of note. Foley Station in La Grande is pretty good; there’s a couple Mexican restaurants I like, it’s a college town. Geiser Grand Hotel in Baker City isn’t bad… and while I haven’t been able to visit Barley Brown’s Brewpub yet, I hear good things.
If you gassed up in Portland (or waited through the lines in that row of truck stops in Troutdale), you’re probably going to want to gas up into Idaho. The prices are better across the border than they are in Eastern Oregon. The Treasure Valley sort of begins in Caldwell, there’s a Flying J and a Maverik near the freeway (both on the north/left side), good bets. If you wait to fuel, one thing to note: you’ll get to 3,500 feet in elevation closer to south central Idaho. Your car will drive better on 85 octane fuel at altitudes above 3,500.
The freeway through Boise won’t usually be crowded going east, unless you’re passing through early on a weekday morning. The only real traffic goes from Caldwell and Nampa into Boise in the morning and back in the evening; once you see I-184 splitting off towards downtown Boise, you shouldn’t have to worry. However, if you feel like stopping for a break in Boise, beware Exit 50 and the descent into Wal Mart/Strip Mall/Garish Movie Complex Hell, with accompanying traffic. Naturally, I probably have to drive through there to get to Sierra.
If you stop for a night in Boise, that’s your problem. 
Well, I have a recommendation or two, but keep that on the side.
If you stop for a break in the Caldwell-to-Boise corridor, I argue you only need one more break on the route, probably around the twin towns of Burley and Rupert east of Twin Falls. The freeway moves faster, you’re hopefully used to the drive now, things are more efficient. Both of the legs are over 2 hours, so if that doesn’t appeal to you, there’s always the little corridor including Jerome and the junction to Twin Falls (city of Twin Falls is 4 miles south of I-84, but another truck stop at the junction is serviceable), then either the last rest area before Utah (kind of nice, especially compared to Oregon rest areas) or just into Utah at Snowville.
BTW, Nevada isn’t too far away – 124 miles from Salt Lake to the border town of Wendover, only 54 miles via Twin Falls off I-84 to the border town of Jackpot. Jackpot is sort of a rip-off in a decent setting. Wendover is more accommodating in a less hospitable setting (near the Bonneville Salt Flats). You can blow through Jackpot down US 93 to Wells and take I-80 from there – adds 1.5 to 2 hours to the trip.
Otherwise, a couple notes. If you hate life after driving up the hill out of Boise and reaching the desert plateau above, just know that this was my commute for 12 years, and yes, it sucks. Also, I-84 breaks up just after Rupert with I-86 heading to Pocatello. The problems: (1) the main freeway heads to Pocatello, so you have to remember to take the exit; (2) there’s practically nothing from Rupert to Snowville; (3) there can be dust storms on that stretch past a weigh station/rest area, you’ll see the warning signs, I’ve fortunately never been in one. I have been in a snowstorm on that stretch at night, and it is a struggle to figure out that you’re still on the freeway. You have to take as much care in stopping as you do moving in either situation.
Oh, snow. I’ve never seen it along the route in October. I’ve run into it in Pocatello, higher elevation, roads weren’t a problem. What I do recall: I’ve always had to wear layers for October Real Salt Lake games. It rained once. It is desert; precipitation is rare in any event. It’s not impossible, but it would be shocking.
I did not make a lot of effort to “learn” Salt Lake City; get in for sports and get out at night (sometimes to Wendover) was my MO. However, a meal at Red Iguana (out on West Temple the other side of the freeway from downtown) is pretty good Mexican fare. Old Blitzz fans kept raving about Rodizio Grill, located in Trolley Square, between downtown and the University of Utah campus.
In any event, have fun!