I'm planning our June 2022 trip and the first two weeks (after a week in Ireland) will include three nights in Kirkwall. I'm thinking about adding another 3-4 days at the end, after our travel partners leave us, to visit the Shetlands. After three weeks away from home, will we find Shetland different enough from Orkney to make the visit worth it? I'm already thinking of a 2023-2024 trip to pick up Islay, Lewis/Harris, and Aberdeen which we'll also skip on this trip. Adding Shetland to that trip might make more sense.
I can just see my wife missing the dogs after three weeks.
The current plan is
Glasgow - 1 night
Oban - 2 nights
Skye - 3 nights
Fort William - 1 night
Kirkwall - 3 nights
Inverness - 2 nights
Edinburgh - 2 nights
maybe Lerwick - 3 nights