There are a great many castles to be seen in this part of Scotland and we can give you detailed routes or suggest which are the best to visit, some complete some in ruins.
Here is one route, you won't be able to see all the castles in one day but can pick which ones to visit as you pass them.
Leave Drumnagorrach on the A95 in south-westerly direction take left turn after 1 mile to Rothiemay (B9117). At tee junction take right on (B9022) to Huntly.
At junction with (A96) turn left to Aberdeen and take 3rd exit on roundabout (A97) to Rhynie and Mossat continue on main road to Bridge of Alford (A944). At Forbes Arms Hotel turn right to cross the river Don and at junction 1/2 mile take the right turn (A980) to Craigievar castle (National Trust Scotland) on the right.
Leave castle turn right and continue on (A980) to Banchory. Here join the (A93) turn right Aberdeen and visit Crathes castle (NTS) on left 1.5 miles. Return via Banchory to Bridge of Alford then on to Huntly. At roundabout at junction with (A96) take 2nd exit and continue through Huntly town through the square and keeping straight on visit Huntly castle ( Historic Scotland) a fine ruin.
From here retrace back to the (A96) roundabout take 3rd exit - Inverness then the 2nd right (B9022) - Portsoy, continue on to tee junction with (A95) take right - Banff. Proceed through Cornhill to tee juction (A98). Take right to Banff where at tee junction turn right past Banff castle through the town and take right turn signposted to Duff House (historic Scotland).
Retrace steps back to (A95) and return to Drumnagorrach)