Ultra marathon training

[Warrenlee]

Gents I need some of your expert advice. Myself and two mates are training for our very first Trans Baviaans in August this year. We are fairly fit. 2 of us did a 153km (2000m elevation) Fund Raiser ride a month ago and found it fairly comfortable with an average speed of just over 21kmph. 

Having a business to run and a wife with 4 children means training time requires planning. At the moment I am able to put in around 10 hours a week on average. That is 2-3 rides in the week with one longer ride on the weekend. Now as winter draws closer its going to get more challenging but I will cross that as it comes. 

My question to you is: what sort of training should we focusing on now??? We are doing the Around The Pot 100miler event in July. 

Any advice would be most appreciated.