Training program balance

I'm very new to triathlon training and I have a knee issue from previous injuries/surgeries that has prevented me from running for about 2 years now.  I did a super sprint this summer and walked the run portion.  I'd like to test things out and see if I can prepare for a sprint and oly next season.  

Looking at my calendar, if I fit in conservative sprint and oly training plans back to back, I have enough time for about 16 weeks of some sort of building/conditioning.  If it doesn't happen and I have to walk the runs, I'm okay with it, but I'd like to try out a run/walk program to see if I can handle it.  The problem is, I'm not sure if I should just focus on that or try to work in cycling, swimming, and weight training.  I don't want to overload in a conditioning phase or compromise my ability to hopefully be able to run again, but I think that cycling has really helped my knee recover, so I don't want to cut that out,  and I'm not sure I can afford time off of swimming, which is a weak area for me.  I've seem some plans that suggest one day a week focused on each sport and three days of weight training, but I'm not sure that's right for me either since I probably need more run/walk time.

I'm not sure what to do.  I'm so sick of sitting around waiting for my knee to magically get stronger--I need some sort of schedule to help me focus on getting started even if I have to tweak it a little depending on my running success.  

I would appreciate any help/advice.  Thanks.