I think you are asking about domicile, i.e. where you vote, intend to pay state and local income and property taxes, get medical insurance, settle your estate when you die. Residence is where you actually live, and that can change throughout the year, you can have multiple residences, as many snowbirds do. One of your residences might be at your domicile.
Ideally, you would be able to get a driver's license and register your vehicles at your domicile, but if your residence is different, and especially if you work, you may find that the state of your residence will want you do get a driver's license, vehicle registration, and pay taxes there.
My snowbird brother had stick and brick in both Michigan and Florida. He maintained Michigan domicile, though he lived there only 3-5 months. He voted there, filed his will there, established trusts with Michigan trustees, maintained Michigan driver's license. He registered and insured his Michigan cars in Michigan, his Florida cars in Florida. Because of the large snowbird community, Florida is pretty good about part time residents using out of state driver's licenses, but can be tougher on vehicle registration.
A tax accountant, he thought he had it all figured out, all his assets went into the Michigan trust. When he died, Florida said not so, and 21 months later, as his representative, I'm still trying to get the mess probated in two states.
I have other Michigan cousins who do the same thing, some with stick and brick Florida properties, others who RV (including one who will leave his RV, and maybe some motorcycles and boats, in Florida). The one who RVs also spends more time in Florida than in Michigan, but his domicile is his rural property in Michigan. It has been throughout a long career building highways everywhere in the U.S.
I have one friend with residences in Florida, Oklahoma, California and Costa Rica. This is for business purposes, there are some business registrations involved. I'm not even sure which one is her domicile, she carries an Oklahoma DL, pays taxes in each place according to what the state says is its share.
Everybody's case differs. It helps to pick the right states. It is not something you need to do in a hurry, as you can maintain your original domicile until you've established a new one. It can take a while to convince the state you are leaving that you are no longer domiciled there, even if you reside in other places. Most of the time, it matters less where you actually reside than where you choose to domicile. South Dakota, Texas and Florida can make it relatively easy to domicile without residing; that's why Escapees works from Texas.
Pennsylvania may not make it so easy to establish domicile as a part time resident, I don't know, I haven't tried. If you are planning to be on the road extensively, I suggest looking at one of the states that makes domicile easy, and not be concerned about the location of your summer campground.