Probably. You already got some good advice on dealing with the UI. And actually, I've done something very similar, moving markup from an existing non-Rails app to Rails: tedious, but straightforward.
But without knowing exactly what you have in terms of db schema and how it translates to Rails conventions, I'd say that's where the bulk of the work will be. Especially if this is your first Rails app.
I would definitely try building out a skeleton app first to play with the models and process flow before even thinking about markup.
Best of luck!
