I think 30 to 50ma is normal on computer assisted vehicles, .03 to .05amps, that would be computer memory and radio memory.
There are also alarm systems and keyless entry to consider.
Check the obvious, glove box light, under hood light, also check that all lights work, 3rd brake light, cargo light can draw power with a non-working bulb.
The 1998 Ranger will have a 20 to 45 minute power draw after key is turned off.
So hard to check power draws right away.
The modules stay "awake" for awhile after key is off
You need to hook up the amp meter without disconnecting the power as well, if you disconnect the power then the module giving you the problem may shut down(like it is suppose to when key is off) so you may not find the problem.
You can use a jumper cable; remove battery cable from battery, use jumper cable to connect battery and removed cable, start engine, let it run for 1 or 2 minutes then shut it down and remove key, now connect meter to jumper cable and battery cable before separating them.
Wait for 20-45min. check meter for drop, GEM will go to sleep and power will drop quite a bit.
Start in the engine fuse box.
Don't forget about the alternator, they can draw power when going bad, remove the B+ cable from the back, to test.