You give, and give and give. You do things for others. It makes others feel good to be able to give back to you. If you feel you can hold up to the trip and that it will be a pleasurable experience you should go and let your friends give back to you what you have given.
Just think "your wheel chair will give them a front row pass".
You know what you can and can not stand up to right now. You will make the decision that is best for you.