You will get an answer from every end of the spectrum on this one.
I think we all have different definitions of intensity for cardio, but I think you should do some form of cardio 4-5 days per week including your lifting.
Clearly your main goal is muscle mass, so again it may be a balancing act between enough and too much.
But I do think our bodies were designed to be much more active than we are. Even if you bust your ass lifting 4 days per week, maybe that would total about 4 hours of intense activity for the week. There are 168 hours per week, 56 should be spent sleeping. So out of 108 hours a week, 4 is spent in physical activity. Not enough.
If you aren't growing fast enough with that, then it is simple to bump the calories.
There are runners who swear that lifting weights can't help them. There are lifters that swear cardio can't help them. Both are clearly wrong, so it's up to you to find the middle ground that works for you.