If all you want is to get the top tier units quickly, find the base of your Medieval 2 installation and open your Medieval 2 folder and follow this path---->mods\Third Age\data\world\maps\campaign\imperial_campaign
Now open the descr_events file. You'll see this information:
; ------------ CORE GAME EVENT --------------
;event historic world_is_round
;date 1 2
event historic large_city_barracks
date 12 14
;date 48 56 turns
event historic huge_city_barracks
date 24 26
;date 96 104 turns
Try changing that to this:
; ------------ CORE GAME EVENT --------------
;event historic world_is_round
;date 1 2
event historic large_city_barracks
date 1 2
;date 48 56 turns
event historic huge_city_barracks
date 3 4
;date 96 104 turns
The ;date lines are
not important at all, they're only there so that people could have a better idea of when the events take place in game.
Now the longest you'll have to wait for the best units will be 4 or maybe 5 years at the most.
At least, that was my experience.