I was, of course, only kidding. 🙂
However, what one of my colleagues does is this: Monday morning drive to work, Monday evening ride home. Tuesday morning ride to work, Tuesday evening drive home. Wednesday morning drive to work, etc.
Now, his journey is only 20 miles each way, which is rather mor manageable, but a 40 mile trip would be pretty good once fit. This assumes he’s going to buy a road bike…
If he’s going to buy a MTB, and currently drives to work (you mentioned car park), then why doesn’t he try driving part way, and riding the rest.
It’s all about biulding up fitness, and if he’s buying a bike for weekend use (MTB or otherwise), he’ll appreciate the fitness gains riding to work can have.