I just went out and checked the o-ring as suggested by MB DOC. It is not leaking there. I used a mirror, a piece of paper towel stuffed under the heater hose nipple, and checked from underneath. The dripping is really from the driver side of the block, not the rear as I had originally thought. And by using a dental mirror I was able to at least see the other hose clamp on the little v-shaped cooling hose at the oil cooler end.

Glenmore suggested using a flex-shaft 7mm nut driver to get the hose clamps. I have some small hook/pick tools I think I can use to get the hose off. Looks like I will have to remove the throttle linkage for access. It is held on by some Allen head bolts. Please God, don't let me break any of the bolts!