The current body style is Brilliant IMO
,why not set it right? The cost will be more if you rip the body off and build a new one.
Well i have no experiences in this field,but a big fan of buses so I'll put up some ideas about making it a successful one:
1)Well its used for Intercity purposes,so comfort is a big thing where every passenger needs while journeying.So Push Back seats is a must.
2) I don't know much of body builders up at the north(Where your bus runs).But here in Bangalore there are many body builders like Prakash,Veera,Azad.etc.
Google the body builders near your place or try any other model at Sutlej itself.