It depends on how long you'll be gone. Fulltimers usually set up a domicile somewhere (South Dakota seems to be popular) and have their mail delivered to a service. FMCA has a service you can forward your mail to and they scan an image for you to see. so you can decide what to forward and what to trash.
FMCA SericeUPS has a similar service, and in addition to a mail forwarding service will give you an actual street address instead of a PO box number.
Most campgrounds will accept forwarded mail. It just means that you'll need to be a certain place to set it up.
Try to setup online bill payments. Most everything can be done online. Then you just need to ensure an internet connection periodically.