lhbernhardt

No way around it. If you want to get good at anything, you've got to do it at least 4x/week. That said, cycling will still be a good way to help with weight control, since your body will just not get that efficient at it if you only ride 1x/wk. In order to do a century in a decent time, you'll need to do some training. It's not just something you can get up and do right away. To get the same training effect, cycling takes way more time than, say, running. I'd say the ratio would be about 3:1, cycling to running. An easy half-hour run is equivalent to an easy hour and a half of cycling. A hard 10k running race is equivalent to about a hard 30km time trial, though both would take about 40-45 minutes for a pretty fit athlete.

If I had a job where I spent lots of time in a distant location, I'd just leave a bike there, as long as the location didn't change each time. Or I'd ride the hotel exercise back. Even 20-30 minutes, as long as you did it every day, or every other day, would help.

Luis

groovestew

Some cycle-commuters will drive part way and cycle the rest. That may not be an option for you either, but may be something to consider.