So. Ca. to McAllen, Tx.

Active duty person should be able to sponsor you on base camp ground. However depending on where you want to be... it's a big base and takes time one end to the other. My info 7 years old maybe changes have occurred? Summer time it gets HOT!
Other campgrounds near or enroute nothing sticks out in my mind.

Most states have a DOT 411 app where you can get road construction info. Actually google maps also has that info.

I-10 has some construction in the Phoenix area. Not too bad, but just watch out for backups.

Once you get through Las Cruces, NM, (where I live) and El Paso, TX on I-10, continue on to Fort Stockton, TX. Stay at the Ft. Stockton RV Park (excellent little home-style restaurant on site). Then go south on US 285 toward Del Rio, TX. Stop at Langtry, TX where Judge Roy Bean, the "Law West of the Pecos" lived. Then on to Del Rio--stay at Lonesome Dove RV Park. Then on to Alice, TX (277, 44) then south on US 281 to McAllen. Stay at Tip O'Texas RV Park in Pharr (touches McAllen). The roads are great, just a lot of them with nothing to look at but desert fauna. We drove that route in March and there is virtually nothing to impede your progress. Safe travels!

Appreciate the responses :)"Webecreekin"-We have stayed at the Ft Stockton RV Park and have great memories of the place, including the "Café" Our truck broke down there-instead of a 2 night stay we were there for a week and we had a great time--plus the owner of the campground set me up with a local repair shop who fixed the truck in a timely manner and reasonable rate. We will definitely make a point of going back there. Thanks :B Lars

At I-10 just before getting into the Phoenix mess you might want to consider picking up Hwy 85 south at Buckeye which will take you to I-8 at Gila Bend, AZ then take I-8 east to join up with I-10 again. It avoids a lot of traffic.

If you're ready to stop around Benson, AZ east of Tucson, Kartchner Caverns State Park is about 10 miles south of I-10 and the cave tour is excellent. The adjoining campground has electric.

Deming, NM would be the next place to stop after leaving Benson. The museum is awesome... a little of everything and very well done. Lots of RV parks in Deming.

Then you'll be fresh to tackle driving through ElPaso, preferable on a Sunday morning.

I agree with 2gypsies, taking Hwy 85 south to I-8 is a good route (we've done it several times).

lhenry, if your wife is ready to stop when reaching the I-8 , there is a KOA near there at 85/I-8, excellent, clean, remodeled KOA. The owner is Scott and is super nice and is working very hard to make that the best KOA in the system!

Once on the I-8, it runs right into I-10 and it's an easy drive.

Safe travels,
MM.

I’ve stayed at the ft stockton lots of time over the years. HOWEVER, last time I tried to stay during hot summer months the highest voltage I could get was 102 volts with no load. Ask a mobile RV tech working where the best electrical service was. He said there isn’t any here. I left there and went to the one on the other side of town. Think it’s the “hilltop” We liked the place over the years, but be aware.

We're planning on stopping in Ft. Stockton on our way to Orlando. Will probably be there Friday.

I have a winter home 10 miles from McAllen. This area has many RV parks for winter residents. They will be almost empty this time of year so you will have your pick of sites and parks. The area is very hot in the summer so I suggest you try and locate a site in a park that has shade for the RV. Tip O Texas is a good park but there are others. If you have only one AC unit your choice of a shaded site will be critical as your single AC will not be enough.

Creekin gave you a good route.... I have used it many times. Just be aware that there are no services for 100 miles between Fort Stockton and Sanderson on US 285. Also Sanderson is small and between Sanderson and Del Rio there is not much in the way of services.