Good luck with it, and please post photos when you complete it as I'd love to see what you end up with.
I think it's good to have different options depending on where you're going/what you're doing. I really like the stroller idea, I'm just not handy enough to make something myself!
Alfie enjoys getting out and about, as he's quite boisterous for a grey and seems to take it all in his stride. He loves going in his aviary in the garden and I have a similar problem in that I can never convince him to come back out of it in the evening! I have to remove all the toys and perches then put the travel cage over him to get him to go in it! Otherwise, he just climbs away!