Inverness to Clava Cairns and Cawdor Castle

You can fit in Clava with the regular bus to Culloden Battlefield, then a short walk.

Does Rick not go up to Culloden one day- giving you the potential to cut free from the tour after Culloden? - may save a bit of time, and money.

But you aren't going to find taxis waiting at either Clava or Culloden, and there is no regular bus to Cawdor Castle - just a School service to and from Nairn Academy.

A taxi is either going to come out from Inverness or up from Inverness Airport, likewise on the return from Cawdor the taxi will either come from the airport or Nairn- Nairn being closer than Inverness. Either way there is going to be waiting time and dead mileage to pay for.

Disclosure, I have not been on this tour. But, I have a few thoughts.

The Inverness Castle Experience - this building was never a castle and is not particularly old for Scotland. I wouldn't make this a priority.

As mentioned in the previous response, you will be going to Culloden which is not far from Clava Cairns. Talk to your tour guide about how you can best fit in in.

Cawdor Castle will require a taxi. I would imagine there will be several others on your tour that would love to join you.

Again, speak with your tour guide. They should be able to help arrange something.

Looking at the itinerary, you visit Culloden in the morning and are then taken back to Inverness for the afternoon.

As isn31c suggests, don't go back to Inverness after visiting Culloden. Clava Cairns is about 1.5 miles and reasily walkable from Culloden. After visiting the Cairns walk back to the Visitor centre to catch a bus back to Inverness. It's a regular service. That gives plenty of time for the Castle Experience. In April last entry is 6pm and it closes 8pm.

Picking up on jeanm's comment

this building was never a castle and is not particularly old for Scotland. I wouldn't make this a priority.

It's true the castle isn't very old but has recently undergone a massive and expansive refurbishment as a new visitor attraction described as an immersive, technology-driven attraction with interactive installations, digital story telling and hands on activities. It is intended as a completely different experience covering landscape, heritage, culture and people. It is very differfent to your usual castle visit. I've yet to visit, but wouldn't discount a visit.

I don't think you have time to fit in a trip to Cawdor Castle. To be honest, this isn't one of the best of the Scottish castles. Don't be hoodwinked as it has nothing to do with Macbeth either. The castle was built 300 years after Macbeth died...

I don't think you have time to fit in a trip to Cawdor Castle. To be honest, this isn't one of the best of the Scottish castles.

I whole-heartedly agree. I went here in 2023 and was not impressed. In fact, I did a quick walk through the castle and left early, as I was pretty disappointed in what I saw. That said, the grounds/gardens were very nice, and if you did make it there, it might be worthwhile seeing them (I think you can get a separate ticket just for the grounds), but given your circumstances, I wouldn't bother. And like Wasley said, the castle had absolutely nothing to do with Macbeth.

this building was never a castle and is not particularly old for Scotland

That may be true of the current building, but is certainly not true of the site. There has been a castle on the site since the 11th century, and successive structures have seen serious action, including as many as 8 sieges (maybe more), it is also part of the Mary Queen of Scots story.
The sieges include 1715 and 1746, as part of the Jacobite risings.
Hopefully the new Visitor Experience will fully explain the full history of the site.