For this age try my patented Handbag of Joy
get a real old granny type handbag with loads of pockets, then trawl round charity shops and pick up things like old camera (you can get 35mm type ones for pennies), notebook and pen, diary / filofax, pack of tissues, little tins and boxes, brush and comb set, powder compact, glasses case with old glasses in, old mobile phone, pocket photo album, purse with a few coins, old credit cards etc, any old interesting knick knacks, and a few small picture books she has never seen before.
Fill the little boxes and tins with the knick knacks, put some old photos (of her and her family and friends, pets etc) in the photo book and stuff the whole lot into all the different pockets of the handbag. Add some little treats like box of raisins or whatever, and you are ready to go. Wait until she is approaching whiny and bored and has already played with all her other stuff and watched a film etc. Just pass her the bag and say "Have a look in here and see if there is anything you would like to play with." Works a treat and is hilarious watching them rummage around through all the pockets.
We started doing this when ds was about 1 and a half, and now he is nearly 4 he still asks for it. It is the same handbag with the same things in it - the trick is to ONLY get the handbag out on a long journey, never at any other time. I hope this helps! It is fun to collect the things for the bag, as well.