Hi there and welcome to this forum. I can't think of many official campsites on the route (apart from Cobleland, near Aberfoyle, and Pitlochry) but if you are willing to camp wild, Scotland is one of the best places in the world (but beware the midgies ). Here's what the Scottish Outdoor Access Code (SOAC) says about wild camping:
Access rights extend to wild camping. This type of camping is lightweight, done in small numbers and only for two or three nights in any one place. You can camp in this way wherever access rights apply but help to avoid causing problems for local people and land managers by not camping in enclosed fields of crops or farm animals and by keeping well away from buildings, roads or historic structures. Take extra care to avoid disturbing deer stalking or grouse shooting. If you wish to camp close to a house or building, seek the owner’s permission. Leave no trace by:
- taking away all your litter
- removing all traces of your tent pitch and of any open fire (follow the guidance for lighting fires)
- not causing any pollution.
I suggest you follow this link to the
Practical A-Z guide for recreation users. NB you have to scroll down to W to find the camping bit (it used to be "wild camping"

). Access rights apply fairly widely in open country, with some obvious exceptions: check the Houses and gardens entry (which is under H) for clarification.
If exploiting your wild camping rights to the full, please be aware of the background and of your responsibilities to leave no trace. Obviously it can be a sensitive issue and just one inconsiderate camper can spoil good relations between landowners and campers.