BTW - I'm also mid-70s (just had my 75th a few weeks ago). We've been in the area for two years now. I have not done the trail to the top of Calavera yet. That's because I had an arthritic hip when we moved in, and the trail to the top was a bit more than I felt comfortable. Not because of the exertion, but because I didn't want to take the chance of being up on the hill and having my hip decide it didn't want to cooperate any more. Then I've dealt with a litany of tendinitis issues post-surgery as my body has been adjusting to the replacement - was in a boot for about eight weeks.
It hasn't been until the last three weeks that my leg and hip have returned to normal. I took the picture while I was on a 2.5 mile loop in the park. I had planned to do a bit less than a mile, as an out and back, but when I hit my turnaround distance I was still going strong and feeling fine, so I completed the loop. During the walk and afterward, I felt better than I've felt walking for about the last six years - before my hip started acting up.
Most of my family members have gone to the top - I'll probably tackle that this weekend.
Trails are very well marked. There are multiple access points to the reserve, and a network of trails (
City of Carlsbad Trail Map). So you can do an out and back or put together a loop, as you wish. (For my loop, I went in on the southeast off of Cannon Road, in Oceanside across from Ocean Hills Country Club, and came out on the northeast side near Lake Boulevard, basically following the west side of the housing developments on that side of the reserve.)
There are several routes to the top of Mount Calavera, of varying steepness.