Kellyjo, according to google maps, Peterborough to Inverarnan is 371 miles, around six and a half hours. Factor in fuel stops and drink/food/pee stops and you're looking at around 8 hours I reckon.
It's a long way to travel if you have to leave on the Monday. Even if you could stay the extra day you'd probably be there on your tod, as those who haven't already gone home will be moving on to other places.
You may find someone to travel up and back with to keep you company though, which would make it less stressful I'm sure.
