Hi Gordon,
  There shouldn't be any problems with installation as Catrike revamped the dropouts so the clickbox for the internal shifting will fit ok. I had the old frame and had to fab a way to use the old Sturmey Archer shift cable setup. You could check with a local bike shop for wheel build costs. You could also checkout  www.prowheelbuilder.com for pricing comparison. I was able to build my own but I was working in a bike shop at the time and did that everyday. The frame does not require any modifications and if you have any mechanical skills at all, the installation instructions that come with the DualDrive are very good. A suggestion for positioning the new grip shift is to rotate it so you can work the 3-speed with your thumb. It is very comfortable and convenient and everyone who rode my trike praised the ease of changing ranges. Take care and if you have other questions feel free to ask. I hope my answers are understandable. Brian Eagleson