I just finished two months of physical therapy, 2-3 times a week, an hour per session. Some moderate weights, mostly working on old and new neck, shoulder and back injuries. Not much leg work, other than the rowing machine.
After the first few weeks I cut back to twice a week. I needed more recovery time and my priority was bike riding. I rode to and from PT, a 6 mile round trip on a roller coaster route so I treated the commute as interval training. Twice weekly was plenty of workout.
It really helped my preferred road rides of 20-50 miles. With a stronger core my overall stamina and efficiency improved. I no longer got dropped on hills in moderately fast group rides, and often reach the top quicker than most of the group. That's a huge difference for me compared with before PT. It was surprising how much a stronger core and arms made in cycling.
Besides improving neck flexibility and strength, I can hold an aero position longer, hang onto a stronger wheel in front of me, or bridge a gap to regain a draft. Couldn't do that before because I couldn't stay in the drops or in an aero tuck on the hoods for more than 30 seconds. Now I can ride for several minutes in an aero tuck, on the hoods or drops. My legs aren't any stronger. My cardio isn't any better. I'm just making better use of what I had.
I'm taking a break from PT for a couple of weeks, but when I get back in the gym I'm going to add some leg work. Mostly to stabilize my joint control better. They had me doing that on my shoulders and it helped. So if some leg presses and squats help stabilize my hips, knees, etc., so much the better.