Endomorph(people with big bones and a high body fat percentage/store fat easily)

I'm 185cms, im around 15 stone and have a body fat percentage of about 20%. I was just wondering about a few things regarding this. I have a good level of cv fitness and I'm fairly strong but i did want a few opinions on certain things
1.Would it do me any harm to try and gain half a stone to a stone over a good period of time of lean muscle to try and make me appear to have less body fat as I will look bigger from a broader set of shoulders and a wider back that will give the appearance of a v shape and the body fat might not stand out as much.
2.Does any body have any other views as to the best form of cardio for people of this body type that differs from high intensity interval training or heavy bag work on a punching bag.
3.Do other people find that anywhere between 15 and 20% is a good body fat to aim for.