I was able to successfully bootstrap Speediboot, and made a ADTpro boot floppy for my Apple IIe. I used the disk image ADTPRO-2.0.3.DSK from the ADTpro/Disks folder for the boot floppy. I booted my Apple IIe ADTpro client, pressed R to receive a desired file, and it gives me a HOST TIMEOUT. I tried several times, and verified the the PC client shows a connection. It errors out each time.
So in the interim, I redid the bootstrap with Speediboot which automatically boots the Apple client after loading. From there, I pressed R to receive, <enter> to view the files on my PC, and selected a file to transfer. It's transferring right now.
Did I miss a step when creating the boot floppy? Did I copy the wrong .DSK image to the floppy?