Jim Macklin wrote:

In controlled airspace, the MEA or MVA [radar] is
controlling unless you have a IAP.

In Class G, you can fly under IFR in IMC w/o a clearance,
but you can't climb into or fly sideways into any controlled
airspace w/o first getting a clearance.

Once a climb to level-off is completed under IFR in Class G airspace
then the aircraft must forever maintain the off-route altitude
requirements of 91.177 unless becoming VFR.