Not sure I can really advise you but I am training for a Marathon and an Ironman but are pretty new to this.
Advice depends on your aspirations i.e. have you any targets in mind and also your current fitness level.
Im a pretty slow runner my Marathon target is sub 4.00hr but if the training goes well it would be nice to get around 3.30 or 3.40.
Fitting it all together:- I cant state distance or intensity as that depends on fitness and goals. Personally I try and split my weekly training into 7-9 sessions over 6 days of the week, 1 is kept for rest.
3 runs (long, medium and short recovery), 3 bike sessions (long, medium and speed reps/hills or spinning) and 2 swims (endurance and speed reps).
There are people on the forums more experienced and qualified than I (ive run 2 Marathons but not done a Tri yet).
I was tempted to concentrate more on the running as the Marathon is 3 months before the Ironman but ive been advised to concentate on the bike as a) its the key ironman stage and b) good cross training without the impact.
Good luck.