I am currently in the process of upsizing a large Access DB to SQL Server and have not found anything to "assist" in the upsizing other than just getting into it and doing it.
A tool that has helped a lot, but has nothing to do with the upsizing as such, is Speed Ferret. With Speed Ferret you can find EVERY place an object is referenced. Hugh help when dealing with an unknown database, or in my case, one that has been built and improved over an 8 year span. I don't remember everything, so Speed Ferret finds it for me.
HTH
Vic