To Bus or Drive? That is the question.

This website might assist you in your planning http://www.traveline.info/

Have fun and enjoy your trip!

I would not bother with going to Aberdeen. Far better to head out to the Isle of Skye. Don’t forget that you can also use the trains. A scenic line starts in Glasgow & heads north to Fort William. From Fort William, the line heads to Mallaig from where you can catch a ferry across to Skye. On Skye, you would need buses. Head back to the mainland at Kyle of Lochalsh for the train via another scenic line to Inverness. From Inverness - train to Edinburgh. If you did not wish to go to Skye, take a bus between Fort William & Inverness - passing Loch Ness.

The trouble with using buses or trains is that you can’t stop to take photos and you will find that the windows don’t open. Far better to drive yourself as it is so scenic. Make sure you specify an automatic car if that is what you want. Zoom down on the roads on Google Earth to see what they are like.
https://www.visitscotland.com
https://www.travelsupermarket.com/en-gb/car-hire/
www.nationalrail.co.uk
https://www.scotrail.co.uk

We have friends an hour east of Inverness and will be going that direction at some point. Funds are limited so I was disappointed to see the train so expensive since there are a lot of miles between our sightseeing destinations. I hear so much about Skye though that we may have to find time to go there. We will certainly request an automatic! We do have one on hold. I will certainly use Google to get a feel for the roads. Thank you!

The trouble is, you are trying to squeeze a 2 week itinerary into 5 days. It takes a long time to get round Scotland. I hope this doesn't include time in Edinburgh.

It's not clear what you want to see other than visiting friends, but Inverness is a long way north compared to your other cities mentioned.

You are at risk of spending more time in transit than actually seeing places. A car will give you the most flexibility. Hiring an automatic will be more expensive than a manual and fewer companies stock them. If your driving licence is only for an automatic, this is what you must hire, I assume. In the UK, if you take a driving test for an automatic, you cannot drive a manual.

Trains should be booked 12 weeks ahead for the best prices, but you haven't got this benefit and travel should be after 9.30 am. Buses are cheaper, but much slower and less frequent, so they are great if you have plenty of time, which you don't.

I think you need to cut the places that you are covering by half and consider taking trains between destinations.

This does not include Edinburgh, which we will have a total of 3 days to see around that area. Our friends are only 45 minutes from Inverness so that will be our base to see the sites there. There are only about 3-4 places I would like to see as we travel north to them (Crathes, Balmoral or Glamis, etc.) which appear relatively close to Aberdeen itself. We could spend all of our time on the east side but I hate to miss the chance to see Glencoe, even if we just drive straight through. We have our international operator permits and an automatic reserved. It is a fine line though, trying to fit in as much as possible without overstretching. Thank you for the advice. We will definitely keep it in mind as we finalize our plans!

Your dilemma is the one that pretty much every traveler faces. Time versus money: which is most constrained?

For me, the answer is pretty simple: I can find more money (skip a fancy dinner while abroad, economize on things back home, work extra, etc). It's much more difficult for me to manufacture additional time (especially time while on a foreign trip). Makes it pretty easy for me to justify faster ways of getting around. YMMV, but Scotland's beautiful, and I'm pretty sure that if you spend the extra money to rent the car and you get to see more, at the end of the trip you're not going to wish you had saved a hundred bucks by taking the bus everywhere. Good luck.