Be careful of the amount of extra cubic feet space you are adding to the existing piece of refrigeration. It may not be able to handle the heat exchange. If you are confident that it can, a recommendation would be to limit this space requirement by using three inch pvc with at least 1/2" inch closed cell insulation on the outside.
Then thread the two lines inside an inch or inch and a half flex tube through the three inch insulated PVC and then inside a three inch tower. The flex tube should extend inside the tower just below the shank. Be certain to seal the entry point of the line into the flex tube with tape. Assure that there are no air leaks anywhere.
If you are utilizing 14 PSIG to keg, build your ten foot line to - 7-1/2' of 1/4" ID line from the coupler attached with
splicer to 2-1/2' of 3/16" ID line to the shank. This will result in a flow speed approximately 120 oz. / min.