Yes it is normal for the pearl to take a few minutes to turn back on if you do a cold reboot. Also I'm not sure why you can't get a good signal when roaming if you have t-mobile. Go to options>network and then see if your data services are turned "on" and not set to "off when roaming". I'm not sure if this is your problem but just try to see if this helps out with your problem.
Hope this helps,
COJO 24