While I've been in the Modern Era for over a week I still need to unlock the Scoped Rifles from the previous age. The first few weeks after entering a new age is always a struggle because it's all about trying to figure out what to focus on. I'm trying to give more time and goods to the Campaign Map since it must have been over a month since I've acquired a new province. The Guild Expedition has gotten harder since I no longer have a tech advancement over the opposing side and it'll be some time before I do. Before I can use better troops in the expedition I need to add them to my city defenders first. I keep getting plundered too so I'm trying to increase my boosts but compared to the player that's attacking I'm not sure if that'll help.
Boost up your Deal Castle as high as you can, and then higher. That will help with the plundering, unless you're just stuck in a really bad neighborhood. One thing that helped me with that was to send friend requests to the frequent invaders, and many actually accepted. Now, the guys who used to plunder me, boost me :)
Deal Castle is getting all my Forge Points right now. It's only one player that continues to attack my city and they're currently in 2nd place in my neighborhood. Even though he's in the Progressive Era he's got a Post Modern Era Champion. Most of the time its only a blacksmith getting plundered which isn't so bad.