Oregon to Texas

My only thought is Utah and New Mexico are going to be HOT this time of year, and personally I would opt for the more northern route through Wyoming and Colorado.

Just looked at google maps and if you go over through CO on US50 it only adds an hour to your drive and is a lot cooler temps.

A lot of Rest Areas/city parks say no overnight parking but that does not mean you cannot stop for 8-10 hours to sleep/eat/etc. There is a rest area on I-70 just before the Moab (191) turn off and one just before "Hole in the Rock" south of Moab. Monticello has a city park and 3 or so RV parks that are not as full or pricey as the ones in Moab. I have not stopped at the RV parks but I have used the city park for an extended rest. The police station is at the park if you want to ask about how long you can stay. I stayed all night in the Cortez Court house parking lot years ago and was not hassled by any police. There is a Casino south of Cortez, CO on 491 with good fuel prices. This time of year you should not have any problems finding empty spaces in southern NM. The mountain areas will be full but it is 100+ at anyplace below 5000 ft.

We use rvparkreviews.com to help us locate parks in any area of the country. If none of the parks have a spot, try freecampsites.net for some dry camping location or campendium.com. If all else fails, try the local Walmart or a truck stop to park for the night. Some of the Flying J's have dedicated rv spots away from the trucks.