Just a few nuggets of info, hope they help!
The Highland Restricted Area is only active 1500-2300 local Mon-Thu.
Tain Range may be able to give you crossing of R610 C or D - but they are only outlying parts and not the main, enormous chunk of it covering pretty much the whole of Northern Scotland. The only way to get access to that is to phone the low flying booking cell and any time I've tried I've normally been told to naff off.
Cruising over at 5000 feet will, thanks to our unique climate
, often be IMC and on a day with any wind, rough as guts! It's a very mountainous area, generally speaking. Icing may be an issue apart from a couple of days in July as well.
Hope you get good weather for it, it's the most spectacular part of the UK and can be stunningly beautiful if the met plays ball!