As others have said, get a UA Explorer card to give you most of the benefits of Silver Premier. Then use your $1000 to bump yourself up to E+ for flights long enough to justify it.
I've maintained UA Silver for about eleven years but may not quite make it for 2016. My Explorer Card will get me a free checked bag, Priority check in and boarding (Group 2). I have Global Entry and have 100% success rate so I don't need the Priority Security line but I think Silver would get it for me.
Although I've had really good luck getting the upgrades to FC, a great deal of my flights involve RJs so upgrades are not an issue and as long as I can get an 'A' seat, I'm not worried about E+ on an RJ.
I wish UA would have a promotion like CO did a few times in the past- for a limited time all miles would count double toward Premier qualifying.