I love that book, too. I read it when my kids were early elementary and preschool aged and it was so inspirational.
I think the best way to make changes in your lifestyle is to be moderate in scope and intentional in practice. So, by this I mean to carefully carve out a reasonable amount of time to practice whatever this new thing is.
For example, instead of saying no more TV, how about saying that 2 or 3 hours on a Sunday afternoons are set aside for a family activity? And then plan an activity that isn't watching a movie together, e.g. go to the park, read some books, make a craft, play a game, go for a bike ride, etc.
It is more appealing to plan an activity and invite a family member to join you than to lecture them to stop what they're already doing.
Over time, as the family discovers activities they enjoy doing these will more easily become a part of daily life and slowly the shift of how a family lives will change.
Also, while I really enjoyed Simplicity Parenting it is helpful to be mindful of the fact that every family's life is different and we can't all replicate exactly what he did. I've lived much of what he described, but not all, and that's okay.
Household manager for 1 husband, a 13-yr-old son, a 9-yr-old son, 2 dogs, 2 cats, 2 goats, and too many chickens.