I certainly can't convince you if you feel that negative about going to a retreat. For me, I get quilts completed, start new ones, get ideas from all the quilts being made, learn how other people do things in a better way (technique, tools), start new hard things without interruption. Two groups I go with found lower costs. One, we rent a closed convent ($50 each for the weekend) and each person is assigned part of a meal to bring/make. The other group, we go to a converted boarding school and they provide meals/lodging/a huge space we leave set up for a reasonable cost- three nights $200, two nights $165.
I plan my projects so they are like a kits in plastic zipper bags, so I don't haul lots of big stuff. I use a collapsible crate from Office Max with wheels and a handle for all the projects and sewing accessories, a machine, a small folding side table, a suitcase, a portfolio case for rulers. I don't think that is unreasonable or bulky. I always come back with many things finished and a healthy amount started. And being around wonderful people who I learn so much from.
But if your mind is made up against the hassle and cost of retreats, so be it. I need them.