Ajo is a nice little town of perhaps 4,000 people between the Mexican border and Gila Bend.  We stayed in an RV resort catering mostly to snowbirds.  Their monthly rate is only $300.  Not bad if you like little towns and want to stay warm over the winter. The small downtown is picturesque with a really large three sided many arches structure with shops, a plaza, and two churches:

We stayed a couple of days so that we could visit the Organ Pipe Cactus National Monument which is in the Sonora desert. The Sonora desert is one of four in the US and is considered a subtropical desert.  The desert floor was green and in places had purple and yellow flowers blooming due to the recent rainy season.  Three days ago we drove north and started looking for an RV park in Sun City.  The going rate was around $49 so we tried to over night in a Walmart parking lot.  Not allowed.  It was getting dark when we got to the north of Phoenix, so we stayed at the Pioneer RV Resort.  This place is #1 on our list of way overpriced for what you get and don’t ever stop there.  $37 and that was with our  Good Sam discount.  Internet was $6 extra.  Cable TV didn’t work – not that we care because we rarely watch TV.  Sites were dusty dirt with no patio and not much room.