Craigendarroch

If you look on Google maps, you will see that Ballater is a tiny place, and you should be able to judge from the scale how far it is from the hotel to the town. There are a few restaurants ranging from chip shops to something that looks more upscale, so I’m sure you’ll find something. Perhaps you should ask the hotel what people usually do to get to the town, as it doesn’t look like there’d be a shuttle. You’ll probably have to bite the bullet and hire a car, otherwise you won’t be able to see anything of the environs.

You are about a mile out of Ballater. The Aberdeen to Braemar bus (which has come from Aberdeen but changes number in Ballater to the #203) passes the end of the drive every 2 hours.- https://bustimes.org/services/203-union-square-banchoryballaterbraemar?date=2023-12-15&service=3353&service=73558
That bus (as the 201 or 202) is your only link to Aberdeen which is 43 miles away.
So you can obviously get to Braemar, into Ballater and down the valley. But the time it takes to get to Aberdeen on the bus restricts how much further you can go beyond Aberdeen in the day and there is no bus beyond Braemar.
And getting to and from Aberdeen takes a chunk out of each day.
So it will be a bit self limiting without a car

As has been said the Craigendarroch is in Ballater and whilst the village is very walkable the Craigendarroch itself is uphill from all the shops, eateries and pubs. There is a local taxi company you could contact to see if day trips could be put together for you

https://muir-private-hire.business.site/

Without your own transport the options are walking up and down to the village proper or catching the 201 bus to anywhere along the A93 corridor. Sadly the railway line between Aberdeen and Ballater was taken up many years ago and where the track used to be is now the Deeside Way footpath

https://www.deesideway.org/

I understand your nervousness about renting a car and suggest you have a look at the Ballater and Crathie Community Group if you are on Facebook to see if any locals have suggestions with regards transport for you.

https://www.facebook.com/groups/259172131651487

We will also be arriving at the same time and have been ging through all the same issues. After much research we have finally decided to rent a car for our time there. Even though we are fairly fit and love to walk the weather is so unpredictable and we did not want to be limited to the grounds or a private driver.
We will be the from the 2nd to the 5th of July. Then on to MULL. Feel free to message me if you want to share the pain of planning this grand adventure 😊
Nancy