1-4 seems to be correct. However, 5-6 could be improved upon.
I would personally transform sentence number 5 as: Penny was grateful to my dad for a lift home.
And your transformation in sentence 6 contains a mistake. You said that: There's point in calling him... Which suggests to us that it is worth giving a try and it's a good idea. Such thinking goes completely opposite to your original sentence, which discourages us from calling. Therefore you need a negation in your sentence to emphasise the fact of not giving it a go.
There's NO point in calling Dan on this number because he has changed it recently.
