Sounds good. Obviously you have to approach encounter building a bit differently in this setup. Your PC is a leader, so presumably it would be a good idea for him to have someone to exercise those abilities on. That would suggest the design of some Companion Characters (there are rules for these in DMG2, but they amount to making a simple purpose-built monster-like statblock which does what you want). So for instance you might have a 'sidekick' and a 'butler' for your hero. The sidekick maybe does certain types of things well, perhaps sneaking, pilfering, etc, or he could be a holy man, whatever (I was envisaging perhaps someone slightly incompetent but who of course always manages to bumble in a constructive fashion, but you can play this many ways). The 'butler' might also be the 'muscle' of the party, silent but tough and able to deal with the more unsavory sorts in an appropriate fashion (this would be a defenderish sort of guy I'd think).
That gives your PC leader something to work with and some backup. I'd expect their adventures would be mostly investigative and 'fixing things' in nature, so there probably won't be a lot of out-and-out full-scale melees, but 3 characters can easily handle a little back-alley scuffle, etc.
One thing I like to remember about 4e is that it is a bit of an action-adventure, and ultimately supers-like, sort of game. It works well when there's lots of 'Indiana Jones' type action. Intrigue is fine, but plenty of crazy lightning train fight scenes are good too! (well, don't be bound by the idea that they are primarily fights, they can be escapes, rescues, whatever).