I'm Cornish born and bred and my friends from Northants made the move to Pz in August. They were originally convinced that Falmouth was going to be their next home (up and coming, gentrified and all that) until I persuaded them to consider Pz.
Yes, it's a 5 hour train journey from Paddington but the GWR WiFi is getting better so you can work as you travel. The current dualing of the A30 will decease the driving time too. This is in contrast to Falmouth which is a dog-leg of a car journey painfully slow across Truro or a change from the branch line to the mainline, again at Truro.
Although some parts of Pz are deprived and run down, it has a lovely friendly, community feel. There are lots of independent shops and it's very arty and 'artisan' but doesn't suffer from the student population that Falmouth has.
My friends stayed in Penzance for as long as they could several times before making their decision, something I recommend you do.
Obviously, I don't know active you are but since moving, they've joined the tennis and gig clubs. They've completed numerous walks along the coast path and swum in the gorgeous Jubilee pool. They've tried surfing and windsurfing too.
They've also enjoyed the cinema, museums and theatres nearby. Not to mention the bars and restaurants.
In a nutshell they're just enjoying Penzance life.
Feel free to PM me for more info. Good luck with whatever you decide to do