Slightly off your direct route but GM/SS-198 East Lomond is about .75miles on easy track from the East car park (slghtly longer from west car park). It’s a
high one pointer. Good take off on VHF and plenty of space for HF.
ES-070 - shortish ascent
ES-080 - fall out of car and a breath of wind will get you there
ES-059 - tracked all the way, great views, probably a pictish hill fort (you may gather I quite liked this one!)
There are others, centre your search slightly inland from Aberdeen (say Banchory, Lat/Long 57.053, -2.498) and there are quite a lot of smallish hills within 25Km - use the find a summit facility on SOTAwatch
In reply to M3ZCB:
Ben Clach GM/SS-149 is a short walk, but no obviopus path. Park on the B827 close to the 234m spot height and head for the summit. 300m of ascent.
Hill of Wirren GM/ES-045 has a good landrover track leading almost to the summit. Go in from the north.
If you’re going up the A93 to Aberdeen you can bag Hill of Persie CS-116. There’s a big layby you can park in. Over the gate, up the hill by the edge of the forest. 35mins to the top.
I have no idea about legality of access on a motorcycle but the track would be rideable to just below the summit with a short foot access to the top. I think the one, or was it two, gates are not locked and you will find there is a cabin, used by shooting parties, in the forest which had a vehicle parked outside it and that is not far from the summit ridge. There is a cricket square round about NO699904 which has vehicular access too.
The route I followed back would be impossible (I hate out and back routes) as it was nearly impossible on foot - via Little Kerloch, then cross country to the farm.