Thanks patty,
Here's a paragraph from that letter that led me to believe Arlo will still be living in Sebastian:

"Meanwhile, I’d decided back in 2018 to move from the home in Florida. And just as I’d returned from our last gig in Tennessee, a buyer appeared, and we had a deal on the table to sell The CrabHouse. I wasn’t in any shape to go through the intricacies of selling a guitar pick, let alone a home with 30 years of stuff we’d collected. Marti ended up doing it all. She finalized the deal, and dealt with the stuff that either had to be sold, moved or thrown out. It was quite a lot. But, through garage sales, online markets, movers and friends, she’d pretty much emptied the CrabHouse of everything, and we moved into her place about a mile away."

I'm assuming that the "CrabHouse" is in Sebastian and that he just shifted to his girlfriend's house a mile away and then went back up North in June. I have a feeling he is of a migratory species that's very common here in Florida during the late fall and winter called the Snowbird. I could be wrong.