Question
I have a big concrete job about to happen in my backyard it is a big back yard and i CAN fit a truck in it. But SOME of the people are telling me to have it pumped. Job is 46 cubic yard 3150 sq ft. Is the job so big I should have it pumped? Also I live in ca in the foothills, HARD, HARD dirt if i'm doing rv park should I do it 4 or 5 inch w/ rebar or not. I have a boat but am getting an rv

Answer
Pumping or driving is really up to you. If the truck will fit and can maneuver to off load the concrete where you need it, then why not? It may tear up your yard if the ground is soft. Pumping will add about $500 to the cost.

As for slab for an RV... 5-6" 3000 psi concrete with fiber reinforcing and steel rebar would be the very best for your area.
Be sure the slab is consistent and minimum 5" not 4" add #3 rebar at 12" oc. each way tie them at each joint. Make sure you cut control joints 1" deep no more than every 10'(each direction_ after about 12-24 hours but not later than 24.

However, if small cracks wont bother you then 4-5" fiber reinforced 3000 psi concrete with welded wire fabric 6x6 or similar will probably be fine also.

Best of Luck