Read fatman to ironman thread
Buy "Be Iron Fit" by Don Fink, pick your weakest discipline and focus on that since we're in the off season...
Assuming you're a half decent runner drop a run session, it won't hurt your mara ambitions unless you're trying o qualify for comrades seeding or Boston
Get in a long bike at weekend as well as your long run, find time for swimming you need to build that base and you need o prepare for open water if you're not already accustomed
You need 30 or so weeks, so tbh you don't have to go all out right now, and assuming you're a decent enough runner I would be focusing on building a basebin the others and deffo my weakest