If you are going to park your camper at your home and not at an off-site storage spot, you will eventually want to install a 50 amp service. At the moment you may "think" all you need is enough power to charge the battery and keep the refrigerator going, but the day will come when you want to use the camper at home, and you'll want ALL electric items in the camper functional.
For the moment, you can get the 50 to 30 adapter, then get the 30 to 15 to keep the battery charged, perhaps run a television, and have power for charging your cell phones (when you decide to do drive-way camps, week-end camps when you can't go anywhere, use the camper for extra bed-room space, a get-away spot when you need some "time out" from your spouse or kids, or the two of you need to get away from the kids, or you want to use the camper for a short term portable office ... and if your camper is at home ... you will do these things!)
Cold weather is not so bad, you don't need air conditioner, but you do need heat, and space heaters help a lot. In the summer, you need air-conditioning, and if your camper has 2 air conditioners, 1 unit will not cut it! And the first time you have extended family over for the holidays ... you will be glad for the 50 amp service!
We used 20 amp successfully for years and years, but when we got our new camper, it draws more power. I ran the wires for 30 amp and had an electrician hook it up. I also bought a surge protector that has an AMP read out, and now that it's 20 degrees in the day time in central Indiana, I'm glad I have the 30 amp because we can run 2 space heaters inside the camper and still run the microwave without blowing any breakers.
Just make sure the electric service you're accessing has space to add another 30 or 50 amp line. The service to our property comes to a 200 amp box. It splits and 100 goes to the detached garage and 100 goes to the house. The only thing running in the garage are lights and the garage door opener. So running a dedicated 30 amp line was no problems at all.
You'll want to do the same thing ... go for the 50 and do it right so you won't have regrets later.