Rainier is a funny mountain. As a triathlete, marathoner, climber myself, I have had great success on Rainier. I'm three for three so far on two different routes. Two of those were in very poor weather, and we were some of the only parties to summit. I attribute it to being damn stubborn and stronger than most.
The first two times I did it I trained like an animal and did great. The last time I did it off the couch and everyone was calling me an "animal" for being so strong. I chalk that up to a good base fitness and good genes.
I would not recommend getting on a two-man rope team with a novice that does not know crevasse rescue. Have I done it myself? Yes. Would I do it now? No.
There is some very good, hard earned advice from all the other guys. Take the time to earn Rainier. I think it is a good goal (one that I attained) to be able to do Rainier without help from other expert climbers- IE- not being dependent on other people for knowledge, expertise, or assistance short of emergency help). Too many people just eek by, just a simple mistake short of disaster. Do yourself and everyone else a favor and get the experience necessary. It bastardizes climbing when you go through the motions without getting the experience. I understand that you have time limitations and I respect that. But don't expect to slide on through without any problems when you try to wing it. Just this last trip we turned around 2 people who were scared, inexperienced, under-trained, and unprepared for the hazards and challenges that Rainier can bring about.