Gotta get my spoke in for Ireland, before you commit to Scotland..
The west coast is particularly well worth a look.. lots of beautiful scenery, quiet(er) roads (than Dublin and that region), great pubs, and friendly people.
Check out Rosaveel in Connemara, west of Galway city, for a lovely drive, and beautiful scenery.
Take a look too at West Cork and Kerry.. The Ring of Kerry should be an interesting drive in a 4x4.
Weather is going to be hit and miss in October.. as with Scotland, the clouds come in off the Atlantic, hit the mountains near the coast, and come down as all sorts of rain.
Lots of B&Bs.. some campsites. In Galway, there are a couple of campsites around Salthill, just at the western edge of the city, within walking distance of the city centre, but really handy for getting out to Connemara.