I drew the frame and forks in 2d first because I didn't know the requirements for what I wanted

After a few changes to my initial design I decided I had the style I wanted. I swept the centerlines of my frame drawing w/2 circles 1 1/2" dia. and 1 3/8"dia. then subtracted the the smaller dia. sweeps from the larger to create 1/8"thick 1.5"dia. tubing for the frame work.
The forks I extruded the 2d drawing an eighth inch then offset a copy the distance for the front wheel then I conected the two forks by extruding a closed arc from an end view. i finished the forks by extruding two circles from the center of the arch and subtracting the smaller

The handle bars were created by joining swept circles

I wanted something a little different from a conventional trike seat. this is what I came up with

the front wheel I made by drawing the cross section of the rim and revolving it around the center axis of the axle. the spokes I made by sweeping a circle from the the shaft to the rim and angling it to get the width then I patterned it to comlete on side then mirrored them to create the other side. the joined all into single part.

the rear wheels are scaled copies of the front wheel without the pedals

The bed I created by drawing a rectangle then filleting the corners. then I converted the lines and arcs into polylines and joined them. I then offset a copy of the closed polyline 1/8" inside. I then extruded the outer polyline 5.5 " and used the shell command to leave the sides and bottom 1/8" thick. then I drew a circle connecting to the inner polyline at the quadrant and offset a copy 1/8" then trimmed the circles to make the curved lip at the top of the sides. After joining and closing them I swept the results around the inner polyline then joined the two solids to create the bed