As Jon says the west coast has some great scenery but can be wet but in June you'd be really unlucky to have a complete washout. A week isn't a great deal of time and once you get north of Glasgow progress on the roads can be slower than you might be used to (even in a bus!). Anyway, here's my recommended itinerary:
Day 1: Manchester to Oban. Stay here... http://www.obancaravanpark.com/" onclick="window.open(this.href);return false;
Day 2: Oban to the Ardnamurchan peninsula. Very short ferry crossing at Corran. Stay at Resipole (http://www.resipole.co.uk/" onclick="window.open(this.href);return false
or at Kilchoan (http://www.ardnamurchanstudycentre.co.uk/" onclick="window.open(this.href);return false
. The site at Kilchoan is small and has a steep entrance so might not be suitable for lowered buses. There's a great beach at Sanna Bay and a visit to the lighthouse at the Point is worthwhile.
Day 3: Ardnamurchan to Morar. Stay at Camusdarach (http://www.road-to-the-isles.org.uk/camusdarach-campsite.html" onclick="window.open(this.href);return false
Day 4: take the ferry from Mallaig to Armadale (Isle of Skye). Stay at the Glen Brittle campsite and be prepared for midges (http://www.ukcampsite.co.uk/sites/details.asp?revid=1091" onclick="window.open(this.href);return false
Day 5: Skye to Applecross over the Bealach-na-Ba pass. Stay at Applecross (http://applecross.uk.com/campsite/" onclick="window.open(this.href);return false
or go a bit further north to Torridon where there is a basic site at Shieldaig (http://www.scottishcampingguide.com/link.php?n=492&c=18" onclick="window.open(this.href);return false
Days 6 and 7: make your way back home maybe staying at Glen Coe (http://www.redsquirrelcampsite.co.uk/index.htm" onclick="window.open(this.href);return false
.
If you don't fancy staying at the sites then there's plenty of opportunity to wild camp. Have a good trip.