Dual Gauge?

Thinking of Dual Gauging Denver to Golden, as was the prototype after 1900 or so (before std only). Included the relevant deck to show change I'm noodling.


Pink dashed line is parts considering for Dual Gauge.  Click to enlarge.

Unsure about all the spurs. Some make sense to Dual Gauge, so not so much.

How would Dual Gauge terminate normally?

Will be slow going as I need to get a jig from Fast-Tracks to build turn-outs. Buying commercially is iffy due to wanting to run code 55 and the $40 each turn-out cost.

Opinions?

Thanks Cameron