Originally Posted by NWIFlyer

There are castles (and other 'old stuff') spread throughout Scotland - the best of them may well be 200 miles apart!

Without some more detail on at some other things you'd like to do, suggesting a single base is going to be nigh on impossible.

For example, are you also interested in visiting some distilleries? If so, you might be best off basing yourself around Perth, where you're within striking distance of Whisky, countryside and the major castles at Edinburgh and Stirling, plus Dunfermline Abbey. If you're looking for smaller, more intimate castles then the advice might be to head further north.