dxo ColorEfex pro 5 would be my vote (because I already have the suite, and use other filters in there often) ….it will give you those nice bright colors, and make all the world a sunny day, oh yeah.
you can also introduce dust and scratches to complete the effect…
but I sort of have to say, blee1996 is probably the best option in that a LUT can be applied to a RAW image, but DXOlab seems to work further down the process chain, and, as someone who actually shot with Kodachrome (back in the olden days from my covered wagon)…the skin tones that DXO applies by default are shifted too far into the reds to be an accurate representation (Just tried it to see…)