A fairly traditional and challenging route might start on the west coast at Inverie (shop, bunkhouse, remote pub!), which you must reach by sea on a passenger ferry from Mallaig.
Head into Knoydart, tackling Munros Meall Buidhe, Sgurr na Ciche (bothy at Sourlies), the head over the Glen Dessary Munros and Sgurr Mor (bothy at Kinbreak), then on to Tomdoun (hotel).
Then head to Clunes, and over the Loch Lochy Munros and maybe Ben Tee to Kilfinnan and along the Great Glen way to Fort Augustus (shop). Take the old military road (the Corrieairack) over to Melgarve (bothy) and then to Laggan and Newtonmore (shop).
Then all that remains(!) is to go east taking whatever route you fancy through or over the Cairngorms and as many Munros as you like (Glen Feshie [bothy] up onto the plateau for Sgor Gaoith, across to Braeriach, drop into the Lairig Ghru, Ben Macdui, Loch Avon [shelter stone] and then a long walk out towards Inchrory [bothy at Faindouran] and Cockbridge along Glen Avon.
From there you have a choice of flattish or hilly routes towards the coast at Stonehaven.
I'd prefer this east to west though. Nothing beats getting into Inverie for a pint at the Forge after slogging across Knoydart.
There are any number of variants - e.g. start at Shiel bridge or Glenelg, through to Kinlochourn (or along the south Glenshiel ridge) and then rejoin the route at Tomdoun. After you go down to Clunes you could then deviate entirely by heading to Glen Roy (bothy at Luib Chonnal) and then to Melgarve. Or you could head to Spean bridge, through the Lairig Leacach (bothy) to Corrour and then east to Ben Alder and then Dalwhinnie (shop), then over the east Drumochter Munros to Gaick and then Glen Feshie. This latter is longer, but perhaps better.
I think all of these variants will require you to be ~5 days away from food supplies. You also don't have to traverse high ground (the exception perhaps being getting across the Cairngorms from Glen Feshie, you would have to go a long way around, but lots of coast-to-coast folk do just that) - it is important to be realistic in Scotland and have a low-level backup plan; when the weather is grim you won't want to be hauling a big backpack over the Munros.