Heritage will run upto MTP from MTP-CBE bluemountain exp available, but then u cant train towards LTT at that time, next day morning u can get it at CBE.
Stay at CBE
if u decide to go via konkan catch CBE-MAQ 56323 upto SRR, then Transfer to 12617 MANGALA LAKSHDEEP exp to KYN u have wait at SRR for 2.25Hours that will have enough time to have Lunch or TODDY avbl at Kerala