I'm a bit late here as real life has adopted a nasty habit of interfering with my internet browsing. Still, a couple of points on travel haven't been made yet.
First, Inverness only makes sense if you are headed to the Northern Highlands. For Lochaber, Skye, Arran and the Cairngorms Glasgow is probably your best bet, closely followed by Edinburgh.
If you are headed north and west (which I would recommend unless you want better guarantees of snowy peaks) you have to pass through Inverness if you want to drive there quickly. In which case Edinburgh or Aberdeen are quicker than Glasgow, especially if you get a cheapie fare to Prestwick. EasyJet fly to Aberdeen early morning or late afternoon, which might fit your plans better than the direct flight to Inveness.
On the other hand, pottering along the coastal roads from Glasgow, through Oban, Fort William, Mallaig, Gairloch and Ullapool is no bad way to spend your time.
March/April is the most treacherous time for avalanche and rockfall in the Highlands as the temperature can climb rapidly and without warning. I have been on climbs that literally melted out from under me, having been bombproof and solid when we set the first belay. Take care if you go offroad.