Training for 14-mile ride & a 5k

I'm a newbie, so I need to know how to train.  I'm giving myself plenty of time and still have a considerable amount of poundage to lose.

In August I've agreed to be part of a duathalon relay and take on the 14-mile bike ride.  Right now I just have a mountain bike but plan on buying a nice bike once I get to goal (that's my reward to myself). Is there a training schedule that I should start with since I'm just getting back on the exercise wagon?

In October I'm doing my first 5k.  Yes, that's a long ways away, but I've never run before.  I want to have plenty of time to train and get used to it.  I printed out a C25k program.  Is there anything else I should know?  Or just dive in?

Who knows?  If I like my results and my training excelerates, I may try some events before then.

You seem to have a pretty good handle on it. I like the "just dive in" part. The c25k will get you started and there are some tri-athletes around who will be able to help out with the biking and transition stuff. Good luck.

At this point, the best thing to do is get out there on your bike and get comfortable... Speed training and hill work can come in time, just get in some good saddle time and get your sit bones used to being in the saddle. HAVE FUN!!!

c25k is excellent, it will certainly have you ready.  You can repeat it over and over, just increase the speeds at which you do it.

As for riding, just get out there and ride.
Put miles in the saddle.

IMO comfort is #1, if you aren't comfortable on the bike you won't ride, you won't be fast for any long period of time because the discomfort will be too big of a distraction.

Before you buy your new bike, go to the local bike shops and ride the bikes.  Most of them have loaner programs that are free or will credit the rental towards a purchase. Ride something more substatial than around the block, take it for a long ride, bumpy roads, smoothe roads, hills, etc see what the bike really feels like.

good luck.

Scott