I did it several years ago and had a great time - enjoy!
As above be aware of the camping restrictions around loch lomond and unless things change between now and when you do it, bothies will be closed. Imagine most cafes and pubs etc along the way will still be able to accommodate you for meals though given how things are moving.
I think my stops were:
Day 1: Wild camped about 2km before the top of conic hill right next to the path (couldn't really find anywhere better and a spot it the forest we'd wondered about had a whole scout troop). Wasn't the best spot but was fine.
Day 2: ate lots of cake at the cafe in Balmaha, yum, then stayed at Rowchoish bothy - was nice, although it probably can get busy (we had it to ourselves luckily) and some people had left rather a lot of toilet paper all around the nearby trees which was a bit off putting. Also, be aware of the pine marten which might try to steal your food in the night as we found out when some of rustling woke us up - hang your food bag from the ceiling if you can! If we'd read the visitor book before going to sleep we would have known about it!
Day 3: Crianlarich youth hostel. Honestly can't really remember much about it, but think it was fine, and nice to get a shower and charge up the battery bank etc.
Day 4: wild camped near Inveroran. There is a lovely spot to camp literally right next to the bridge that we'd heard about but got mixed up about where it was so ended up camping about 300m beforehand in some trees that were full of midges, and not really that nice. We then passed by the intended camping spot first thing and were pretty disappointed to have missed it because it is a really idyllic location next to the old bridge and the river, lovely views etc. Oh well!
Day 5: 'wild' camped behind the Kings House Hotel and had a delicious meal in the pub area. I believe since we were there the hotel has had a big extension and basically tripled in size, but still encourages nearby camping and has an informal pub area where smelly walkers will feel comfortable
Day 6: don't think much was open in Kinlochleven when we got there mid afternoon on a Sunday and remember thinking it was a pretty grim place (weather was really grey that day which probably didn't help). We got some supplies from a coop and ate most of a coop cake sat on a bench there though which was good
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We then just carried on walking and the rest of the day was pretty drizzly so although we had planned on camping somewhere sooner we just carried on walking until the daylight started to fade. Ended up camping in a tussocky little patch of grass in the trees next to the forestry track about 3km from Fort William in the end. Not a spot I'd recommend as such but it was fine. I'm sure there are much nicer places to camp between Kinlochleven and Fort William, but with the weather and also being pretty tired and just being focused on reaching the end point we weren't really interested in finding somewhere 'nice' at the time.
Day 7: finished! Went and sat in the Nevisport cafe for a couple of hours eating stuff and drinking hot chocolate until the next train back to Glasgow left
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I guess my main advice would be to eat meals in pubs / cafes wherever you can, as it can be a real pick-me up having a good meal. We could probably have done more of this if we'd thought about it, but then we still got by and saved a bit of money (which was a priority at the time!).
Depending on how your days break down, I guess my two main recommendations would be camping at Inveroran, and camping near the Kings House Hotel.