Thank you all for your responses.
@JayG80, thank you that is what I was thinking. The rust is mainly located on the fenders, the running gear isn't showing much rust.
@jhughes fortunately I do not have to travel far for the new one. I am going with a loadmaster trailer, which is custom trailer manufacture that is about 20 minutes from my house.
@Hockdog, two reasons. First is a space issue in my garage. Current trailer does not have a swing away tongue, which I need for the space in my garage. Next I have started trailering the boat to our summer place which is a bit of a hike from the house and it makes me nervous trailering the boat that far on a 21 year old trailer even though the running gear appears to be in decent shape, never know what is lurking where you can't see. I have always kept it serviced, but after a incident that I had with my truck and the boat last year, the hitch that was bolted to the frame of the truck rusted through at the welds and it snapped off while trailering the boat back to storage. So the unknow things you can't see, internal rust, has made me a bit uneasy with the trailering the boat on a old trailer long distances.