Reykjavik on the west coast is a 2–3hr flight from a variety of UK airports.
Once you’re in Iceland, overland travel can be difficult if not impossible in winter, so if you need to go any distance you’ll be reliant on internal flights. Because of the terrain, there are no railways here, so to explore you’ll need to hire a car – or, at least in the case of some of the most popular natural attractions, join a tour. You can also hire motorhomes, but the road conditions here are on the rough side.
You could easily base yourself in Reykjavik and take tours to the Blue Lagoon and Golden Circle from there. On the other hand, this is a small country, measuring only about 500km across, so you won’t be covering any vast distances even if you do choose to branch out from the capital.