Suggestions for RV panel install, long run

Just thinking that if you run a mobile home and an rv it's common to run 100 amps. Doesn't mean you must. If you were running two AC units and two microwaves you'd be hitting 60 plus amps probably. Doesn't mean you will be doing that but...

I have a 30 amp FW and micro and ac pull 30 amps together. No matter what you want the wire sized and breaker sized so the wire doesn't become the fuse.

Thank you for the responses. So perhaps run underground in 1.5" non-metallic PVC (25 x 10' sticks @ $6/ea), skip cable and go with individual wire. I WOULD like to save money, so maybe 750' of #1 aluminum, plus 250' of ground. I haven't priced thick aluminum, but I'm guessing maybe $.50, $.60 per foot?

I'd be running off the service pole which is 200. That feeds my sister's house, and they run crazy power, so I don't want to try to pull a whole lot. azrving, why do you say I will likely be running 100 amps?

Yeah, I was thinking with #1 aluminum I might need to go 2" PVC.

Consult a wire chart. You would most likely be running 100 amps out there. As mentioned above you need four wires because you are running a sub panel out there. Two hot, neutral and a ground and it's NOT bonded. The bond is already in your house main panel so you remove the green bond screw in the sub panel.

Neutal and ground are bonded at the source so your house is the source now and should be bonded.

Will you be coming off the main panel for service to the house?

Also be extremely careful if wiring a 30 amp RV pedestal. It's very common for electricians to mistake it for 240 plug and smoke your RV appliances.

If using aluminum it needs the proper compound at the connections. Be sure there are zero Nick's in the wire or it wire corrode to powder even if in conduit. Go big on the conduit so you are fighting it.

I just pulled out three strands of number 6 180 feet because the last owner dipstick didn't run a ground. It was a pita because it was only one inch PVC. Place n 8 foot ground rod near the panel and another one 8 feet from the first rod. Use the appropriate gauge of bare stranded copper ground from sub panel to first rod then continue on to second rod. Use acorn nuts. You can cover it with dirt but keep it outside the drip line of any structures.

At that distance, if you are really drawing 50 amps then #4 copper is the minimum to have your voltage drop below 3%. If you want to save some money you could run #2 aluminum. However, with just one 30 amp trailer initially the situation isn't as good. Pulling 30 amps at 120v means you would need #3 copper or #1 Aluminum as a minimum to be under 3% voltage drop.
Personally, I would run aluminum to save some money. Also, I put everything underground in conduit. Conduit is cheap versus getting the cable damaged, finding the damage, digging it back, up, etc.
Don't try to pull a multiwire cable thur conduit. That is extremely difficult. You would pull individual wires thru the conduit. Alumiium wiring will be type XHHW, copper will be type THHN.
Individual conductors in conduit are usually less expensive than UF cable and much easier to work with.

would would need to find 6/3 with ground direct burial wire or run 1.5 inch conduit with 3 #6 wires plus a #10 ground.
Personnally I would use 3 #4 wires plus #10 ground.