We (6 adults) are traveling to Scotland from the US in late June. I have researched several travel books and spent lots of time reading what has been posted on this board. We enjoy seeing the countryside of the places we visit and we like to allow time for stops along our routes. Each couple will have a designated driver and we plan on renting a larger van to accommodate 6 people and our luggage. We did this in Ireland and it worked well although some of the roads were very small considering we were in a van. Our accommodation tariff guideline is 45 pounds or under per person per night, with a night or two splurging up to approximately 80 pounds p/p/p/n. Other than sleeping, we do not spend much time in our rooms. We are open to B&B's, Guest Houses, Inns and Hotels. Suggestions on the following proposed itenerary will be very much appreciated.
Day 1: Arrive at Edinburgh Airport around 9am--Pick up rental van and head to Callander with possible stops at Linlithgow, Falkirk Wheel, Stirling Castle, Wallace Monument. Overnight for 2 nights in the Callander area.
Day 2: Enjoy The Trossachs/Lake Lomond area (overnighting in same place as previous night.)
Day 3: Travel to Glencoe (with a stop in Killin). Possibly going to Port Appin for an overnight--need some suggestions here.
Day 4: Travel to Mallaig and ferry to Isle of Skye for 3 overnights.
Day 5 and 6: Enjoy the Isle of Skye.
Day 7: Travel to Plockton via the Skye Bridge and then back to Eilean Donan Castle and on to Urquhart Castle. Here is where we need some help to complete the itinerary before returning to Edinburgh. We would like to overnight somewhere between our visit to the Urquhart Castle and Edinburgh without driving non-stop to Edinburgh. As I mentioned earlier, we would like to take our time and enjoy the route even if it means a one night stay.
Day 8: Arrive in Edinburgh and return the rental van. Overnight for 3 nights in Edinburgh.
Days 9, 10 and 11: Enjoy Edinburgh before flying home on the 12th day.

Is this itinerary too much for 11 days? Comments/suggestions will be appreciated.

My views on driving unfamiliar vehicles in unfamiliar countries on unfamiliar roads after a long haul flight are simple - DON'T.

Spend time in Edinburgh first recovering & getting used to the pace of the UK road system

My rec would be the same as alanRow's. You do have the advantage of having 3 drivers so one will possibly be fit enough to drive. But it is also likely that most of you will totally space out and miss Linlithgow, the Wheel, Stirling and the Monument.

I'd put Edinburgh (sans car) at the front end and then follow the rest of your itinerary as planned. This pushes everything back 4 days - but you could do the same route and spend the last night just about anywhere w/i and hour or so of EDI (Perth, Stirling, Crieff, etc etc.)

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It's almost as easy to go from Stirling to Edinburgh Airport as it is to go from the centre of Edinburgh - as long as you avoid weekdays before 9:00am or between 4 & 6 pm the journey from Stirling is probably about 40 minutes

Bumping this version up

Sounds like you have it well thought out. You've gotten some good suggestions though.

We will be in Scotland at the same time. We can't wait!