You're looking at at least $3000 for the parts, likely much more.
The 69 grille is the biggest $$$. Many parts to it including a vacuum system for the headlight doors. The headlight switch and wiring is different from a 70 since the 70 model has an electric motor for the headlight doors. The fenders, hood, bumper... all different.
I breifly considered a 69 clip on my Charger in 2000 but the 70 style grew on me.