Liam,
Grew up in Inverness and went back there to do my IMC. Inverness has (had?) its own micro climate which I think is thanks to the jet stream. As such weather is not as much of an issue as you might imagine.
The airport itself is about 15 miles from the City Centre. Easyjet and several other commercials operate to from Inverness. There are 2 runways plus ILS, DME and VOR. They also have radar.
The flying school scene has undergone quite a bit of change since I was last there but overall it was very GA friendly compared to other airfields of similar size.
Assuming you are going VFR you have 3 basic options to get there from the south;
1. Direct via Perth. If you have good cloudbase then you can route pretty much direct over Cairngorm. With a lower cloudbase you might prefer to track the A9. The highest point is Drummochter Pass where the road is 1500' amsl and the hills either side rise to 3000'. I have done this with a 2800' cloud base but you need to be careful with turbulence off the hills.
2. Up the east coast and then keep west of the Aberdeen CTR routing via Bancory/Inch. This stays clear of the higher aspects of the Cairngorms and you can cut the corner depending upon the cloud. This takes you quite close to RAF Kinloss and Lossiemouth. Lots of Tornado traffic so LARs service is a good idea.
3. Up the west coast past Prestwick to Oban and up the Great Glen to Inverness. The Great Glen only gets to about 100' amsl but its quite narrow in places with 2000'+ hills on either side. This is probably the most scenic route and adds the possibility of visiting many of the west coast gems on your way north. Oban, Glenforsa, Coll, Colonsay and Plockton are my favourites.
If you are planning touring the Highlands then get in touch with HIAL in advance and get an out of hours indemnity which lets you use many of the HIAL airports outside operating hours.