1. Basecamp cannot be used for navigation with a GPS receiver, it just allows you to use Garmin format maps on your computer and exchange data with their dedicated GPS devices.
2. IMO, there really aren't any good Windows programs for this anymore. Garmin used to make a program called MobilePC that was pretty good in its day, but it is discontinued and no longer available. There is a very old program called nRoute that still works with Garmin format maps but is really outdated. Very awkward to use on a tablet and also sluggish.
Have a look at this recent thread, a variety of options are discussed: http://www.laptopgpsworld.com/5588-i-lost-my-pc-garmin-mobile-pc-looking-alternative