My DH hurt his foor badly playing football about a month ago. At the time I was sure he would be fine for the holiday but ten days out he is far from it.
Don't get me wrong, he can walk fine but has a limp and is in pain after a medium amount of time.
There is no point making him walk if it's going to cause pain of any kind, at the beginning, middle or end of your day, since it will start to impact on your holiday and the experience. Nothing is worth that. If the wheelchair will make the holiday more enjoyable for you, and for him, then do it
I was thinking of getting a push along wheelchair so that he can actually enjoy his days in the parks rather than endurng them. Could we park it up like you would a stroller and go onto rides?
Depending on the ride, you can go right to the ride vehicles in the chair, or park outside and walk in if that's more comfortable. Most rides have separate entrances/passageways to get you to the ride anyway, and there is generally a space to leave the chair when you get there.
Depending on how you are feeling, HM, for example, you can leave the chair outside the exit and have a CM escort you straight to the stretching room if you are up for a couple of minutes walk. Alternatively, they can take you in the chair right to the point where people get off, slow down the ride, and load you at the exit, leaving the chair just outside the doorway.
Different rides have different systems, so just let the CMs at the entrance know what you are and are not comfortable about doing and they will do the rest.
He is also very worried that he would be taking one away from someone who needs one more - especially since he will be able to get up and walk away from it.
He needs a chair just as much as the next person. Although it is hard to stop the thought process, he really has nothing to feel guilty about. He might be able to get up, but he still has an underlying condition. My mum always feels guilty going in her chair. She has a heart condition, and from looking at her you would think nothing is wrong. Most of the time she is fine, but some days are just more tiring than others and she can't do the distance. Yes, you get looks from people, but they don't know the truth. You know he needs it, he knows he needs it and that's all that matters. Why should a few strangers who you will never see again have to come into the equation? Again, easier said than done, but that's what you have to keep in mind.
Also will I be able to push the thing? (
ECV seems a bit beyond budget!!)
That is an entirely personal decision and judgment call. It is not an easy task to push someone around all day, but as long as you are fit and healthy it won't be too much of a problem! Obviously, the larger the person in the chair, and the smaller you are, the harder the task will be!
Animal Kingdom is probably the hardest park to negotiate with a wheelchair, since so much of it is up and down hills, and it's always hotter there because of the environment. AK is the only park where we will generally push mum in her chair from the car to the rental place and then rent out an ECV. The rest of the parks are generally fine.
The only really difficult ride (pushing wise!) to get on is Space Mountain. You don't notice the steepness of those up and down ramps until you have to do it with a wheelchair. Also, getting out of the ride is just as precarious as going in! The moving conveyor belt goes up and down quite steeply too, and if you do not have firm control of the breaks, then you'll know it!

The breaks on the rental wheelchairs are also not that spectacular either, so just watch that when waiting on hills!
Hope that helps a bit. Anymore questions, and I'll be happy to answer!