What a great birthday present.

I liked Callanish, who wouldn't. It's epic. But I think I liked this better
https://www.themodernantiquarian.com/site/199/ceann_hulavig.html
because you could have it to yourself. It's just down the road.

Also this is superb, and you will be glad if you go
https://www.themodernantiquarian.com/site/1277/bostadh.html
https://www.visitouterhebrides.co.uk/see-and-do/bosta-bostadh-iron-age-house-p523981

The satellite rings would all be worth long trips in themselves anywhere else.

Would also recommend:

1) Airigh nam Bidearan stone row
2) Dun Carloway
3) Clach an Trushal
4) Steinacleit

Get there early in the morning (and I mean early, before the visitor centre's even open) to avoid the crowds, particularly if the sun's up when the low light is fantastic. Also yes, don't miss Ceann Hulavig and I would also go over to Bernera Bridge, a nice (short) drive and an appealing setting.

Had a look on the Portal...Dun Barabhat looks good...access at low tide. My sort of place. Not on TMA - yet.

I agree with all the other posts - especially about Bostadh. Walked there from the house we stayed in on Great Bernara on the one day it was warm (May). On the way back we saw a golden eagle sitting on a ridge watching us before taking flight. The first and only time I've seen one - a precious memory (many other amazing birds too).

If you are going by ferry from Ullapool I would suggest you take a travel sickness pill before boarding the ferry. Speaking from my own experience the scrambled egg and smoked salmon breakfast in the B&B was not a good idea. The Minch was choppy that day and both myself and travelling companion were very sea-sick.

Happy 50th when it comes around.

There is a standing stone on the opposite side of Bernera Bridge from Callanish 8 that Moey and I helped Margaret and Ron Curtis resurrect way back in 1999. Pictures on the TMA.
When are you off?
Joolio