What could Millard have needed help with to cover his tracks and help him 'escape?'
-wash his clothes
-destroy/dump his clothes that he wore the night Tim Bosma was murdered
-help wipe his phone, his computer history
-help move his vehicles, move the incinerator?
-get MB to be 'elsewhere' so that Millard could store his trailer on her property
-provide a false alibi for Millard somehow
-help dismantle Bosma's truck into parts, remove identifying numbers from TB truck parts
-allow DM use of another vehicle or storage of his vehicle with her
-disposal of firearm or murder weapon
-cleaning up his vehicle to remove evidence
not sure if these qualify for accessory after the fact/helping to escape. This would happened three days after Bosma's murder.
I think most/all of those would qualify you as an "accomplice", not "accessory after the fact".
Duchaime: "Person(s) that aids, abets, advises, or encourages the commission of the crime. "
http://www.duhaime.org/LegalDictionary/A/Accomplice.aspx