As long as you have a 7-way at the rear of your motorhome that has active turn signal/stoplight circuits and has a 12 volt accessory circuit as well the part # TK94FR will work regardless of the brake setup of the motorhome.
The Prodigy RF brake controller # TK94FR has a 300 foot range so the 40 foot you listed would not be a problem.
I attached an install video for this controller for you to check out as well. view full answer...
The replacement step you need for your 2004 Monaco Dynasty is the Lippert Components Kwikee 35 Series Single Electric Step # LC3691462 based on the number you gave. Let me know if you have any further questions. view full answer...