May seem an unlikely question to be answered to any degree of help as too many caveats, however ...
what would people who have been think the total cost would be for such a trip.
Base it on average hotel and sensible drinks!! ( ok how many rounds to be bought!)
Flights are in the £100-150 region (probably a max) depending on where you are coming from. Try
SkyScanner but don"t forget the "extras" that might not be listed.
Hotel: can be had for £60 - 70 a night (standard)...cheaper options exist and I can investigate if you want. Obviously, quality increases by cost.
It"s not outside the realm of possibility to fly in on Saturday morning and return Sunday night (again, location dependant) but that assumes you don"t FT (or it finishes really early).
Essentially, for Londoner/Southerner/Welshian...it"s probably about the same as travelling to Scotland.