It is feasible, but a fair commute.
Much closer and easier to reach (and therefore a lot cheaper) is Dundee.
Hotel prices in Dundee are usually a fraction of those in Edinburgh.
Just had a look at one budget option I know- Jollys Hotel in Broughty Ferry (a suburb of Dundee). They have a single room for all 8 nights at £945. While a lot more than normal it's probably a better price than Edinburgh when you take commuting cost and time into account.
See what Dundee City has.
I can see the Corn Exchange at Dunfermline for £845 for the same 8 nights. Again quite a bit closer
Just had a look at the Salutation at Perth - one of "my" hotels in the area (admittedly much the same travel time as Edinburgh)- room only single £677.20.