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...
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...