I have fabricated the bracket to accommodate the RockyMounts bike rack. So far I have invested $7.50 for the 18" of 5/8 - 8 ACME Threaded Road, $272.00 RockyMounts Tandem R4 Bike Rack, $4.00 5/8 - 8 ACME Nut (qty 2); $15.62 for 1" OD x .625 ID x 5 LG for Spacer Pipe & 1/4 x 4-1/4 x 15-3/4 plate. $10.00 for 1-1/8 OD x 5/8 ID x 4-1/4 LG Steel Tubing.
This is what it looks like right now...
From the pictures I needed to order an additional bike rack support from RockyMount $10.00. And on the right side tow hook mount I need to add an additional plate to be welded.
Total Invested is $319.12 for a bike rack design that can hold my single or tandem bike.