I answered your mail and 'Blue Boy' questions on your other post on 'the' other forum. :) I suggested you wait on the dump tote until you see if you really need it. We lasted up to 14 days on our tanks and by that time we were ready to leave anyway so dumped on the way out.
However, you just stated you're keeping the house and having a relative living in it. So really...you don't need a mail service. The relative can surely do this for you. You can even instruct him to toss catalogs and flyers.
Leave some 'postage money' with the person. Keep your address as is. He can glance at the envelopes to see if they're important or not. He can just put all the mail received in a box and when you come back into town you can go through it.
If he sees something that might be important, if you trust him, have him open it and text or email you as to what it is and if you need it to be sent to you. He can send it at the RV park you're staying - if they allow it, or we always had our mail sent to: Our Name, c/o General Delivery, City, State. Definitely pick a small town post office so there won't be any issues. We never had a problem in 16 years of full-timing. The P.O. will hold it for you approx. two weeks so just allow 3 or 4 days to have it sent and picked up. We always used Priority Mail from our mail forwarding service. We even did this in Alaska.