If you can't find a used/refurb 27xx or 28xx, the Nuvi line does have some models that allow for custom routes.
It ain't the same as a full blown streetpilot series 27xx or 28xx, but it will get the job done for most novice tourers.
I run a Nuvi 755t and it does what I need it to do, for now. It was <200 at Costco.
The key is CUSTOM ROUTES. When you download your 1 free map update from Garmin, you will get a copy of MapSource as part of the download, which you can use to build your routes.
PS: the Nuvi's ain't waterproof, so keep that in mind....