Yes, I've driven from Trogir/Split into Bosnia and Herzegovina twice, once to Mostar via the coastal road and the E63, and then back down to the coast and on to Dubrovnik. (And back via the Peljesac Peninsula, and the ferry Trapanj - Ploce.)

The other time I drove inland through the most gorgeous scenery and countryside to Sarajevo.

I've written quite extensively about these trips, and you can read the details in the following trip reports...

http://www.fodors.com/community/europe/mostar---a-city-of-beauty-and-bullet-holes.cfm

http://www.fodors.com/community/europe/off-the-beaten-track-in-bosnia-and-herzegovina-juliat-explores.cfm

And while I flew directly into Sarajevo on this trip, it may still have something of interest to you...

http://www.fodors.com/community/europe/sarajevo-in-the-springtime-juliat-makes-a-return-trip.cfm

Also, look out for vttraveler's name and then click on it. She has also travelled through BiH and posted detailed reports.

Just get yourself a good map, as detailed as you can, and do keep to the main roads. There are very good reasons why these little white roads are not used as more major routes between places! Remember, white roads = white knuckle drives! But otherwise the roads are perfectly good. Be aware of the rules for driving in both Croatia and BiH (there are differences) and keep to the speed limits.

Yes, and to add to Julia-T's comments - the locals drive like idiots. Beware.

Thanks very much Julia_t and Toronto Steven
Meera