Season off of Tris--Ultra and Century

Hello.  I have decided to take the year off from triathlons because of a hectic work schedule requiring last minute traveling.  However, I wanted to do some events so decided running and biking are things I can do if I am at a hotel.   I have decided to do 2 half marathons, 1 century ride, and 1 ultra marathon.  The century and ultra are both on very hilly terrain (ultra is a trail run).  My question is should I focus more on building muscle and strength in my legs and forget speed.  I have incorporated a weight training regimen but it only has 4 leg exercises.  Should I do more?  Any advice is much appreciated!