I highly recommend this to all writers. Especially if, like me, you have to juggle writing with day jobs, family, and other responsibilities. The benefits are numerous.
To sum up: Focus. Total focus. I cannot emphasize this enough. You don't have to worry about getting dinner on the table, about helping the kid find his Crocs or the hubby find his glasses, or about anything but your manuscript.
My advice is to go somewhere a reasonable distance from your house. However, make your destination someplace familiar, that way you won't be tempted to go exploring, and you won't have to wonder where you're getting dinner that night.
Try to avoid distractions. Leave the iPod at home. Bring your laptop, but leave the internet cable at home. If you bring books, make sure they're old favorites you've read before so you aren't getting caught up in them.
I find that even in my downtime, I'm not worrying about any of the myriad of things I normally have to think about. I can focus on one thing: my book.
In addition to the edits on Undertow, I brought Boswell The Laptop with me and was able to get work done on the work in progress. Up to 48,000 words now (technically I passed 50,000 but I realized that a chapter needs to be narrated by a different character and so I have to redo it).
I also did a bit of book shopping. Yes, I know I'd said I wasn't going to buy anything new until the Festival of Books in April (you in the back, stop laughing). But times are tough, Solvang is one of my favorite towns, and I supported local businesses like The Book Loft and the newly opened use book store, Valley Books. Came home with books by Stephen King, Neil Gaiman, P. G. Wodehouse, and Cormac McCarthy. Good times.
Oh, and I ate a lot of pancakes while I was at the retreat, too. Editing makes you hungry.