In reality you will commit to far too much to have any relaxing days. You may get to walk through the park but it will be a rushed, sweaty walk that you are taking just because you have somewhere to be, and of course, you're late.
You will join baby groups, maybe even a slimming class for yourself, you will be expected to take the baby into work and to see friends/relatives. Those days you dreamt of in which you would relax on the sofa cuddling up with your baby watching Disney films don't happen. How are you supposed to fit lazy days in now that you have committed to all of these groups and people? It doesn't matter anyway, your baby doesn't even like cwtches and finds watching TV incredibly boring.
You will always be late, in the early days it will usually be because your baby has a poo-nami just before you leave. Cue a bath (or at least a full body wash using wet wipes depending on just how late you are) and complete outfit change. In the later days it may be because your baby has had a lie in and you daren't wake them because if you do all hell will break loose. It could be because baby would rather sit in their highchair and shake their head instead of eating their breakfast because shaking their head is hilarious and breakfast isn't. You will find yourself scooping their lovingly prepared breakfast into a plastic bowl with a lid and taking it with you.
Don't get me wrong, I did manage to get some things done. I completed an on-line photography diploma and managed to spend a little more time and effort on my blog. Aria slept a lot which meant that I could do these things sometimes. I even made most of my own purees following the Annabel Karmel plan. Nowadays she sleeps a lot less so generally has fish fingers.
Maternity leave probably won't be what you expect it to be, but it will be fun.