I would suggest that you stay in multiple locations, so you can go further away from Glasgow (unless that's what you're the most interested in) and visit other areas, such as the Highlands, etc.
I'm not sure if two weeks is enough for the type of travel I'm suggesting. Perhaps, you should choose a few places (with different "personalities") beforehand, and spend a few days in each place.
Another suggestion, even though you're travelling alone (I assume), you could look up a tour group's itinerary and base your travel plans off that. You could start with this one:
http://tours.ricksteves.com/tours06/...rurl/code/SCT/
I have no clue how good this itinerary is, but judging from the map, it seems to be a nice loop around Scotland.
I'm sure others here will be able to help you out more.
Best of luck with your trip!
Quick EDIT: The itinerary I linked to assumes you arrive in Edinburgh. But seeing as it ends with Glasgow, you could try doing it backwards. Remember, you're not in the tour group, so alter whatever intinerary you find as much as you want!