Can't really travel around with work, but would be cool to meet up at Concert or events! Even if you're not part of the FC there are still events like the upcoming Tsubaki mini lives on the upcoming Sat, and both a Yanagawa (13th) and Juice Juice talk event (7th) at the Hello Shop. Since Angerme is releasing something new I'd except some events from them as well. Although currently only handshakes are announced, they should be doing a variety of things and mini lives around the release period. Also, there is the H!P Countdown at the end of the year (lost the election last year but won this time so will be there from afternoon until the very end, yay~), and although I guess you won't be here at the beginning of January, that would be H!P paradise as they have loooots of Hello Cons and good seats are relatively cheap. Then there's the Morning individual handshakes which you can probably buy handshake tickets for on site if you're early. Keep an eye on the website event page if you want to attend as much as possible.
I took a look at the viagogo site and the tickets are undesignated and general sales ones...you can count on them being terrible seats. Try out
or otherwise Yahoo Auctions, if you want to buy the best seats at the lowest prices since the tickets on those sites are directly being sold by end customers. Yokohama Ticket has physical locations and you'll see which tickets they have at which shop on their website in front of the ticket (you can currently check it out with the Momusu Pacifico Yokohama concert, Up Front sends the tickets out ~2 weeks before the concert date),but they are more expensive and mostly have bad seats. Of course you won't require an address for Yokohama Ticket so that is the advantage. I am going to the Shizuoka Concert on the 25th, their Budoukan and JJ's Budoukan.