I've really been craving DnD but can't find a real life group so I think I'm going to just play with my girlfriend and DM. Most of my friends either aren't interested in DnD or don't have consistent schedules (and neither do I), so it'd be easier to just randomly play with my girlfriend rather than schedule something out.

To the point: what have you found to work well when playing with just a single PC? Does it work well? Should I load her up with a party of NPCs (I know this is normally a no-no but I feel it'd be an exception if she's alone)? Should I let her control said NPCs? Should I have her make a gestalt character (two classes with all the strengths of both)?

I'm a fairly newbie DM and this will be her first time playing so any advice at all, however basic, would be appreciated.

:Edit: This is 5th Edition, by the way.