The RAF moves me quite often... usually to somewhere where I don't know anyone... so I am used to this!
I will usually go to the bar in the Mess and talk to random people... this is how I will meet people... Then, on my first weekend hanging around, I will check out the local town on my own, and normally go for a walk in the area to get my bearings...
Finally I use the people I have met at work and in the mess to reccomend me things to do, or to come with me!
I travel the UK quite often too, to see people in different areas, so quite often see new places and spend time with them as visitors!