We used "Traveling Mailbox"......they have different addresses across the US that you can use and the highest cost is $55. a month. We did the $15.00. They have a great website for looking at the mail and YOU determining if you want it forwarded, returned, shredded, etc. We had absolutely NO problem with them all winter long. Just google "traveling mailbox". :)
As for mail "sitting there". My SIL sent us some goodies from Jelly Belly to a PO box in Quartzsite. She was told it would be there in 2 days, but it didn't get there in 2 weeks and we had left. It apparently sat there for over a month, then showed up at our home. The PO tried to charge us $12.00 for the forwarding!!!!!!! I denied it, refused to pay.....sent it back. By that time the company had forwarded us a new shipment...... just an fyi!