<<" Ok, so in the interest of getting to Kleine Scheidegg as inexpensively as possible from Wengen and let's assume I have a Travel Flex Pass Combi. I do not see the Mannlichen(Sp sorry) lift showing? Can you tell me adult cost?">>
I think you are pursuing a good idea.
I cannot find the fares to do the comparison, but it would likely be cheaper to ride the gondola lift from Wengen to Männlichen and walk the 4 km on a really scenic trail to K.S. Wengen to Männlichen lift opens May 30.
That would take you maybe 90 minutes to walk.. Gently downhill. Generally, boots are not needed, just sturdy shoes, but I am more comfortable wearing them.
The stretch of rail from KS to Jungfraujoch is the most expensive part, however, so you might not save as much as you'd like on the total package.
<<"And further can a 75 year old in fairly good condition hike the route that sort of follows the train route? ">>
I've done it in the other direction. It is an 800 meter elevation difference. The trail is generally good. I vaguely remember a few stretches with ruts and rough surfaces. On my Wanderkarte #254T it shows as a regular Wanderweg, not a Mountain Trail, thus boots are not required. You might find that you prefer the ankle support, and definitely should have sturdy shoes with good soles .
When I did that walk, going down, at least 10, maybe 15 years ago, I was generally fit but had not been training with long walks, and by the time I got to Wengen, my knees were quite tired. Stamina was not a problem. You'd not have the knee trouble going up, but you start at 1274 meters above sea level (0.8 miles) and finish at 2061 meters (1.3 miles). if you are not used to hiking at those altitudes, you will likely find it very tiring. It his hard to make judgements for these things based on other peoples physical conditions and experience. Today, at age 76, I would not try it until I had been climbing shorter distances for a few days at those altitudes. And, i would not want to. The Gondola car from Wengen to Männlichen +the trail Männlichen to KS is faster, easier , and much much more scenic.
And, once you are there, you'd probably prefer use your time to do the most spectacular part, and resign yourself to the fact that it is expensive. Once again, to each his own.