i haven't done this for over 2 years now so i have no clue whether its changed or not....

but coming back to my earlier point....i was heading to mauritius a few years ago & there was no direct flight from delhi....i took a domestic ic flight from del-bom & then was to take a connecting ai bom-mru flight a few hours later....i had no checked-in luggage since i was only going for a couple of days so i caught a cab from the domestic terminal....combined with a little bit of rain & some construction work, it took me a little under 4 hours to get to the international terminal....they had pretty much closed the check-in counter by the time i got there but they let me get on board just because i had no luggage to check-in....

my point is basically while it won't take more than half an hour for the op's wife to transfer between the 2 terminals, she will be much better off getting near the international terminal first & then meeting whoever she has to meet there....she will have her pick of over half a dozen hotels that are less than 5 minutes from the terminal....