I would not suggest the Bolt as an appropriate car for a road trip in the American west. Even if you think the specs will work for you, it just is not a great EV for the expansive distances. The range is much lower than most other EVs, and--even worse--the charging is far slower than what other EVs support (only about 50kW, meaning it takes over an hour to (mostly) fill the small battery, vs nearly half that with most other EVs, even with their larger batteries.

Running a search from Crater Lake to Vancouver with an initial SOC of 70%, ABetterRoutePlanner.com says:

• Tesla Model 3 Long Range: 37m of charging, 10h18m total
• Polestar 2 (single motor): 1h8m of charging, 10h49m total
• Chevy Bolt: 1h56m of charging, 11h41m total

The limited range also makes the trip much less flexible. If you arrive at Crater Lake with only 25% SOC, you have to make a fairly significant detour south to charge in Medford before heading north, and your time would jump to 3h26m charging/15h7m total, and if you arrive with 15%, you're SOL--there are no chargers within range. Deparrting from Crater Lake with the same 25% in the Tesla would result in only 53m of charging and 11h11m total travel time--a huge difference. Also, there's a Tesla destination charger at Mazama Village on the south side of Crater Lake, so while it's a slow Level 2 charger, if you are in a pinch and need a charge, it'll give you enough to get out of the mountains in an hour or so--not sure if you're aware, but in the US, Tesla uses a proprietary connector that is not compatible with other EVs, and they also have invested in the most widespread and reliable charging network (which also works by just plugging it in, no cards or apps necessary--Hertz passes through the charging costs at the end of your rental).

The CCS1 charging network in the US is a mishmash of third-party providers, the largest of which (Electrify America) is a halfhearted (and government-mandated) effort by Volkswagen to atone for the sins of Dieselgate, but they don't seem particularly good at (or interested in) maintaining stations once they've completed their obligation to build them. I was just reading this Reddit thread last night, and while the topic (charging a motorcoach) isn't directly applicable to this question, the extensive comments section really gives a good illustration of charging infrastructure and reliability in the west--infrastructure in between major metros can be spotty, and if it does exist, it can be unreliable (some stalls not working and/or some stalls working at reduced charging speed). That's something you can work with in an EV with a big enough battery to get to the next station, but with the Bolt's more limited range, there may be places you end up a creek without a paddle.

I've also personally experienced being at the only CCS charger (not EA--I think it was Shell Recharge or a Shell partner) within 100 miles in a rural part of the UP of Michigan and finding the credit card reader out of service and the charger's Internet connection buggy enough that the app was being frustrating (got it working on the 6th try, after calling the provider and having them remotely reboot the charger). That kind of thing happens more than it should be allowed to happen, but it's a fact of life in this early stage of the game. I'm not sure how much of an issue a non-US resident would have signing up for accounts on the various networks' apps; they don't ask for ID or anything, but the biggest concern I'd have is that US e-commerce merchants usually rely on credit card AVS (Address Verification System) instead of 3DSecure, and many European cards don't support AVS and will fail a transaction that doesn't support it, so a European card may fail when you try to add funds to the account. You may be able to get around this by getting a Visa/MasterCard gift card (widely available at grocery stores, gas station convenience stores, Walmarts, etc.), which should pass AVS no matter what billing address you enter in the app (use your hotel's address if you need).

I personally wouldn't do that trip in a Bolt. It's a fun little car to drive, but it's an around-town commuter that can be used on a longer drive in a densely populated region with some patience, not a long-distance western US road-tripping car. You could try making a backup reservation at Avis just in case, and then reserving the Bolt and asking for an upgrade to something else upon arrival, and if the Hertz price for the upgrade is unreasonable, just ask them to cancel the transaction/reservation and go over and pick up the gas car from Avis.