Bicycle Mechanics - Vintage 105 Downtube Shifters to Bar Ends

I'm doing some office wrenching (sitting in my office, wasting time, and thinking about my bike).

I recently picked up an '88 Trek 520 and have decided to convert my Surly Cross-Check to a single speed monster. I love the bar end shifters on my Surly and would prefer them to the downtube shifters on the Trek. Should the modern pods/mounts work with the vintage levers?

I don't understand the question. Do you mean if the bar ends will fit into your...bar ends? I think the answer is yes. You will need DT cable stops also.

I'm doing some office wrenching (sitting in my office, wasting time, and thinking about my bike).

I recently picked up an '88 Trek 520 and have decided to convert my Surly Cross-Check to a single speed monster. I love the bar end shifters on my Surly and would prefer them to the downtube shifters on the Trek. Should the modern pods/mounts work with the vintage levers?

They should work. I've used vintage DT shifters in shimano pods a hand full of times before. To be sure, unscrew the bar end lever form the pod and test fit your DT lever in there. If the holes for the cables line up, then you are good to go.

and if that don't work, you could try this adapter:
http://www.rivbike.com/product-p/sh21.htm
(http://www.rivbike.com/product-p/sh21.htm)

and if that don't work, you could try this adapter:
http://www.rivbike.com/product-p/sh21.htm
(http://www.rivbike.com/product-p/sh21.htm)

They are actually exactly the same in design, so if they don't work on your shimano ones, they won't work on the riv pods.