My scanner is not that great to do slides. However here is one from a slide I took as we did an engine change while in Chateauroux, France in 1963 during the U.N. Congo Operation. You can see the flat front of the nacelle that was the firewall, that was exposed when we removed the engine QEC. The rectangular shape in the firewall is the door that we opened to get access to the accessory section... You are right that we could not get to the power section in flight, only the accessory section.
Going out through the crawlway to the inboard engines was not much of a problem. There were smooth wooden floor panels, painted olive drab, and I could slide ourselves along fairly easy. However, as you got out farther towards the outboard engines, the crawlway space became lower. I only weighed about 145 lbs then. I would have to take off my parka during cold weather and push it along in front of me until I reached the outboard engine. Then I would put it back on to work.
I also went to school on the R4360-59B used on the C-97. However, I never worked on the C-97. There was a SAC KC97 refueling squadron at Dover for a short time during my C-124 days there. We were MATS or MAC and they were SAC. They never associated with us. They had their own security and kept us out of their area. Our only association was that they taxiied at high speeds through our C-124 parking area on their way to the runway. We had to get out of their way or get run over.