Hi all. I'm new to this. I have 5 acres of farm and am going to build a barn for several purposes. The greatest portion is for RV storage rental units. I need to know how wide to make the units. They will be 48' deep with 14' high doors and either 12 wide or wider units. Would you or others want wider, like 14',16' or 18' wide? Would the wider units be good for RV's with slide outs and storage doors to open and still walk around for pretrip and posttrip packing? Also people will just be storing units here and do they just need 20 amp 120 volt power outlets? I don't want heaters etc. running all winter as that would be expensive for me.