Leap of faith with some questions

Congratulations on your decision, and you will have many, many more questions as you prepare. We made the leap this past June and no regrets. Here's what we found:
Laundry: we have a full size washer and dryer in our rig, and my wife does not mind laundromats. She can get all the wash done at one time rather than an all-day event with one unit. But it is super convenient to have laundry equipment with you.
Heat: if possible always use electric rather than propane. The park generally pays for electric; you pay for propane. In freezing weather you need to run some heat on propane to keep the underbelly warm.
Mail: we opted for a mail address at a UPS store and periodically forward our mail. It gives us a physical address where we vote and pay taxes from. Your state of residence will be a decision you have to work through. Many advantages/disadvantages that are individual preferences.

First off, you really need to read the forum rules about duplicate posts.
As to laundry? Your either going to become very familiar with laundrymats or your going to want an RV sufficiently large enough to have a closet plumbed and wired for an RV washer/dryer.
Laundrymats is going to mean weekly trips to town and a day wasted doing laundry.
RV washer combos is going to mean adding about 300 pounds to your trailer and smallish loads that take time to do. We opted 12 years ago for the combo and do not regret it one bit.
As for heat? If you have sufficient power, ie 50A, then by all means electric with propane backup.
Mail? Lots of mail forewording services. Get all your bills set online notification, and pay them electronically. Remember without a house you are only going to have maybe three or four reoccuring bills a month.

It looks like you've wanted to do this for a while but I've done no research, just Google a couple of your questions there's millions of answers out there.

Is your Jayco camper made for full-time use ?

Take a look at the Escapees Club. They can offer help with mail services. Many campgrounds have washers/dryers that you can use. If boondocking, seek out a reputable laundramat in any town you are passing through. With respect to heat, if we are staying in campgrounds, we use the electric heaters. We will only use the propane furnace as a back up. We avoid boondocking in the winter. Running the propane furnace all night will rapidly deplete your propane supply. Further, if not hooked up to electric, you will run down your coach batteries a lot running the furnace. Good luck.