In the second picture it's pretty obvious where your Fleetwood Pace Arrow 37C is parked. In the third it looks like you have fairly soft soil SO I would have 4' x 4' x 6" thick areas for the tires when parked and 4" elsewhere. In each 4x4 area I put 20' of 1/2" rebar in a H pattern. The rebar needs to be 2" from the bottom of the pad.
The edge of the strip coming in needs to be 6" thick for 1' and I would put a piece of 1/2" rebar centered in it. You need less gravel (thicker concrete), not more gravel.
I would use 3000 psi with fiber concrete and no other wire/steel. Wire mesh is a joke, especially when it's not pulled up from the soil. If the pins are gone on the concrete hoes of the contractor, you need to get a different contractor. The concrete needs to be sawed every 10-12' to control where it cracks... yes it's going to crack.
No I have not poured any concrete... this year.
You can see some I did last year
here.