The Swagman E-Spec Bike Rack for 2 Electric Bikes # S94FR has a 70lb per bike capacity when mounted to an RV, like your travel trailer. You would need to reach out to the manufacturer of the trailer to determine the weight capacity of the bumper to ensure it can handle the weight of the bikes and rack. If it can then you can use the Curt RV Bumper Mounted Hitch # C19101.
If not, then you'll to install an adjustable mount trailer hitch receiver. To find the correct size you'll measure... view full answer...