Go to the Orkneys and see Skara Brae

9:51 here
I actually liked Inverness. We stayed their 4 nights as kind of a "home base" to do a few day trips. We stayed at the Premier Inn River Ness, which was basic, but clean and walkable to lots of great restaurants! We especially liked Rocpool and Cafe 1.
The restaurant at Premier Inn was great for breakfast too and open much earlier than other local places. All of the staff was very friendly and helpful, and there was a Tesco around the corner which was great for picking up a few snacks and incidentals.

One of the day trips was to the Culloden battlefield. Their visitors center was amazing (the short 360 degree video they show is a must see! Powerful!) and they have a guided tour (for 2 pounds per person) that was very informative. Since we didn't rent a car, we took a taxi (just walked to the train station and there were plenty lined up) to the battle field and then took a bus back. It was very easy (but have exact change for the bus fare!)

We were just in Portree a few weeks ago and happened to have been there the weekend of the Highland Festival. It was super crowded during the festival - at least an hour line to get into the festival itself (we bailed). Also, as 09:51 pointed out, the popular hikes were very crowded unless you go very early (which we did) - in some of these places, tour busses would pull up & 50 people hop out to have their photo taken. If you hike, the farther up and away you go, the fewer people. You should book lodging & restaurants in advance.

Be warned that in many places in Skye, there is only one lane to the road, so it can be very slow going what with having to pull out and/or back up to a pullout frequently. We took the overland route going to there, and the ferry coming back. Ferry was better!

For the bugs, you can get netted hats and a local midge spray. They’re not everywhere, but when you encounter them, they’re evil. Think swarms of gnat-sized mosquitoes.

Edinburgh was very crowded as well. Inverness was kind of dull. Glencoe was stunning. Ft. William was uninspired and jam-packed. Aviemore was lively, but lots of well-organized activities, that reminded me somewhat of Acadia. North Berwick is the town Bar Harbor dreamed of being.

If you want to hike in August in Scotland, I'd be equally concerned with the biting bugs! Midges, I think?

We did Skye in the fall and were REALLY glad it wasn't crowded. It would have been terrifying to do those one lane roads with heavy traffic!

+1 to the 9:51 poster. We were there a few years ago and Skye was a bit of a zoo. Getting across the bridge into Skye took forever, parking at Old Man of Storr or the Quirang was a mess, and there were traffic jams everywhere out of Portree. The Highlands (Oban, Glencoe etc.) were less crowded though, but yes you would bump elbows on most hikes. The trouble with getting up early was that most of the interesting spots were still foggy and wet. Admittedly, seeing a ghostly Old Man of Storr is quite an experience but I would not say the same for hiking the Quirang in fog.

Check out https://www.walkhighlands.co.uk/skye/ for some nice walks. The Trotternish is highly recommended.

That said, we did not have to book lodging more than a couple of months in advance.

We did scotland last summer and stayed in Morar. Took the first am Ferry to Skye and drove around. It was amazing.

https://www.airbnb.com/rooms/25409087?source_impression_id=p3_1567173536_IVM%2BHx9DzuiFkmX0

I used to live there as a child. Great memories. The weather doesn’t always cooperate, which is why August is a safer bet. Although one year we had a snowstorm in August, and all the southerners were so surprised!

I’d visit in August, personally. Yes, there will be some crowds, but honestly there are far worse crowds in other touristy places...

I was just there 2 weeks ago. The isle of Skye was very crowded.
I'm not that confident in my driving skills on the other side of the road, so we did not rent a car but hired a private guide instead. At many of the well known sites (Quirang, Old man Storr, etc.) there was no where to park; that is when I was really glad we had our private driver/guide because he dropped us off so we could explore while he waited and searched for parking.
If you do choose to drive yourself in August, I would start your touring days VERY early in the morning so you can be out (and find parking!) before the bulk of the tourists are up and about.

OP here, and loving all these recommendations! Thanks so much.