Pitlochry is nice can be expensive to eat but cheap for gifts/ outdoor wear, last time i was there I was dismayed to find a branch of the Gold Bros empire.
you can do a cruise on the Loch however, it can be very cold, and misty

Culloden is a very emotive place, i dont know if the visitor centre will be open but it doesnt matter if its not, its worth a look, there are plenty of taxi firms