I think the pub Nebankh is talking about is between Luss & Tarbet cannot be more specific than that.
To make the most of your visit you have to plan your route in if you are coming up from the east side of the country then Rosylin chapel will be convenient and easy to see. It will also be easy to see Edinburgh.
However, if you will be starting off slightly further from Loch Lomond so will have to spend longer travelling if want to go to Loch Lomond.
If you start on the east coast you could then go onto to Stirling and then to Pitlochry (a picturesque town with some lovely walks) or you could go to Fort William and onto Fort Augustus (two more lovely towns. (check out AA route planner for distances etc)
If you come up from the west side of the country you hit Glasgow and have easier access to Loch Lomond. Despite what a previous poster comment on Glasgow it is a great place for a night out. Try the Merchant City for bars & restaurants, its directly in the city centre so hotel accomodation should be easy.
The west coast gives you good access to Ayrshire (Burns country) and also to the Western Islands (absolutelely fantastic scenery). You are also about an hours drive from Stirling.
To make the most of your stay I would plan destinations & routes so you know how much driving you have to do.