Step up from HIM to IM

Morning All,

I am in week 3 of my 3 month training program for a HIM (Western Sydney - Nov 29), I did it last year and have done Half Marathons and Marathons before.

I am thinking of keeping my HIM base and moving forward to the IM in Melbourne (March 20), but during december, scaling back, but still keep ticking over with some long runs / long rides, just a few more days off, then to pick back up mid Jan for 3 months.

Do you think that will be enough time?

Where I live at the moment is difficult to get up and do any long rides during the week, although I can save them for the weekend and can look at possibly getting a indoor bike trainer.

Any thoughts / feedback would be greatly appreciated.