I looked in the manual and I didn't see a quick/easy way to disconnect the battery. Is the only way to do it is to go through all those steps? Or is it easier than it looks?
Also, am I right to think just disconnecting it is not enough. Should the battery charge the whole winter?
I have a trickle charger but nowhere to plug it in.
Depending on how cold it gets where you store your bike you don't need to take the battery out. If it's near freezing, but not frequently or far below just leave the battery in the bike with the tender hooked up to it. Make sure you get the battery out if it's getting really cold or consistently staying below freezing as the gel can freeze, crack the battery case, and ooze all over your bike (can possibly ruin it).
And to answer your question - the only access for the battery is what the manual shows - remove the oil coolers, air snorkle and gas tank. Unfortunately, no, it is not easier than it looks. But it's not too bad.
Finally, disconnecting is not enough. Best case is to leave it installed, hooked to battery tender at least once every month for several days. If, as stated above, temps drop below freezing and stay there - inside storage or daily rides are mandated.
Just a reminder. If you have a genuine BMW battery still in the bike you can't use just any Battery Tender on it. Search the board for that information. You either have to use a genuine BMW trickle charger, a certain model of Battery Tender, or the Battery Tender Jr... from my research.