Best to have a Factory Service Manual........best money you will ever spend!

 

Yes it can be changed on the ground. I would not go 15w oil. Do a search in here, most found 10w too heavy. The stock oil is 5W and screamin eagle 10w. I used Amsoil shock proof in my 2012, it's about 7w and is much improved.
You won't need a manual, there is a good video on Youtube giving step by step instructions.

 

You need in the air so you can take the end caps off. Might be able to get away with two 2x6 screwed together. Then drill 3/4 hole and use long pipe in the end of wood to pivet bike up. Never tried this on the hog but used to do it to a Vulcan to change motor oil.