I‘m a Sailor(RS500), and I'm about jealous that you can do something like that. I can't chill out on my gliding dinghy and spend a weekend. very nice boat
It can be difficult to estimate as it really depends on usage, place of mooring and how tidy you want to keep her. For a mooring at Cameron house this would be about £4000 a year- elsewhere on the loch you would be about half the figure. Service costs annual would be £4-500 on top of that would be fuel and any modifications you would want to make