Ugh. 

It's embarrassing... I've ridden maybe 3-4 times since my last summer's bike trip. Granted, I did climb onto the stationary bike a few times last winter while I watched TV.   Sometimes I even pedaled.  My excuse is the same as it always is, and it's rock-solid: 

I'm lazy. 

So, dragging my butt onto the saddle again wasn't easy. There's one huge motivating factor that got me going.... fear.  I took a bike trip once  with only some half-assed training before leaving and after several days of "discomfort," (i.e. only being able to feel half my ass, and wishing I couldn't feel that half)  I vowed NEVER to do that again. 

Something to note, your legs/knees/lungs may not be in the best shape but, surprisingly, the main distance-limiting factor is your butt. THE single thing that keeps you from riding forever is how long you can sit on a bike seat. 

That, and a very small amount of common sense.