First of all the trip is easily done in a day. :) There at least a couple of routes. For either one of them, it's easy to stop and see Eilean Donan Castle if you are interested in it. It's the one that is beautifully situated on the Loch and is often on calendars. :) One route takes you north. If you really wanted to take two days to do this, then at Achnasheen you could head west and explore Torridon. You could go as far west as Gairloch. Alternatively, you could go west to Applecross a little earlier. The scenery is quite spectacular. Or, you could just drive right on to Inverness and enjoy the scenery. Stop near Garve for the waterfalls and rapids. It's a beautiful drive.
Or you could take the southern route which takes you past Loch Ness. Just before you get to Drumnadrochit and all the Nessie Tat you'll see Urquhart Castle. This is a great stop. The visitor center is wonderful and it's fun to clamber around in the castle ruins a bit. Great views of the Loch!
If you are looking for alternative places to stay than Inverness, my suggestions include Strathpeffer, Fortrose, Beauly, and maybe Nairn on the other side. But Inverness is a great place to spend a night or two. There are good restaurants, good music and it's easy to make day trips from there.
Pam