Ughhhh. Walking and biking will not be increased unless density is drastically increased, and I do not see how that can be done in a non-coercive manner. Walking will get you 3-5 miles in an hour, biking probably 10 to 20 miles, and outside of major cities very few people have commutes much over half an hour.
Use of trains is limited by use of them being cheaper than downtown parking, and going from where people are to where they want to go.
If you have to pay to park downtown, your town is too big.