Tour of the Cairngorms is an obvious one.
Park at Blair Atholl and do the circuit from there:
http://www.offroadadventures-online.com/rr014.html.
We did that (or something very similar a few years ago) This was our route plan: http://www.everytrail.com/view_trip.php?trip_id=176282
DAY 1 Blair Athol — Loch Morlich Youth Hostel,
DAY 2 Loch Morlich Youth Hostel — via Tomintoul — Braemar Youth Hostel
DAY 3 Braemar — Blair Athol
None of us were as fit as we should have been. Day 1 took 11 hours but we did spend some of the that sheltering from snow in the Gaick Pass! Most of it was ridable but there is some boggy carrying on Day 1 and some bits on Day 2 where we pushed. Day 2 was at least as long as day 1 – and if you arrive in Braemar at 8pm food may not be easy to source! Day 3 seemed “short” at only 5 hours!
As for bothying – the idea appeals but means you’ll need to carry food, sleeping bag etc – which is a lot of extra weight and space.
If I was doing it again I’d either train much harder or split it into 4 days – B.A. — Kingussie; K.U. — Tomintoul; Tomintoul — Braemar; Braemar — BA.
No midges in early May 09, but a route near Kinlochleven at the same time the following year did have some (but not enough to be a significant issue) – but there is always the risk of significant weather at any time of year so you need to carry appropriate gear for that (you’ll be 15+ miles from a public road / house for several bits).
stevemtb Trip round Skye would be pretty spectacular,
is there a logical route “round” Skye which avoids spending lots of time on road – or is it just day loops?