Need an Introduction to Tiny Core? Or peruse Core Concepts.
tce.installed and bootlocal are wrong places for an X app. .X.d is the right place.Make sure it gets executed (echo "me here" > /tmp/rdesk-text), and that rdesktop does not return any error (maybe your network is not yet up?).
Do i put: "echo "me here" > /tmp/rdesk-text" as is in the start.sh in .X.d?
Also, what to do if the problem is as you say, that the network is not yet up?
Wait until it is up before launching rdesktop; there are several code examples of that in this forum, both sleeping and pinging some server.