The fee areas are well defined and there is a registration building, basically a wooden portable building to pay your fee and get a tag. The one we viewed was Imperial Dam LTVA. The registration area was near the dump station and potable water stations.
If you go to Google Maps and search for: 32.901364, -114.494436 then view "street view images" you will see the dump & water station as well as the near by registration building.
Again in Google Maps using the satellite view you can view the boondocking areas that extend for a few miles to the west and north west of the registration/dump area. You basically drive on the paved road and then turn off on to any of the gravel roads to an unoccupied gravel place you want to stay at.
Here is a link to a BLM map of the Southern CA & AZ LTVA areas:
https://www.blm.gov/documents/arizon...m-frequently-0
If you do an internet search for BLM LTVA you will find links to more info. Or search for BLM LTVA "camping" or "rules" as well.
I think you would enjoy this area more if you have a toad. Trying to explore the areas, especially down gravel or dirt roads is not something I like to do in an RV
In 2017 we stayed in the area in one of the free 14 day stay areas so don't have actual experience with the LTVA.
We spent several days at the Mittry Lake area. Specifically up on a level raised area with nice views at 32.815755, -114.474097 If you go to Google Maps and search for that GPS location and then go to the Street view 360 degree view you will see what it looks like.
We also enjoyed several days in the KOFA road area along King Rd: 33.253611, -114.224331 The first 2-3 miles have verizon cell reception. If you want piece and quiet, continue SW along the road for another 2-5 miles for boondocking spots with no one else around.
If you are interested in meeting up with a very informal, friendly group that is gathering at the KOFA area for about 10-14 days starting on Jan 22, go to this forum topic:
KOFA 2021
Post on the topic you would like to join them for a few days and they would be happy to give you more details. We stayed with the group for 3 days in 2017.
An area we enjoyed much more than the Yuma and Quartzsite areas is Anza-Borrego Desert State Park in Southern CA. We boondocked at the Blair Valley area: 33.037652, -116.409548 A very interesting hike at Blair Valley is the Marshal South Home trail:
https://www.hikespeak.com/trails/mar...orrego-desert/
The state park has volunteers who give guided hikes, check at the visitor center for info.
A great SP volunteer lead hike I took when we were there is the moonlight hike. We hiked in the full moon for about 4-5 miles w/o using artificial light. We started the hike just before sunset and continued until 11-12 o'clock.
There are many more hike all throughout the area as well.