Ryan,
This is a wonderful blessing and it is even better you are in a unique position to give/serve more. We are in a similar spot (kind of): I am 32, married, 3 young daughters, no debt, and no mortgage. My job has me working and my family living in Beijing, China. We are not missionaries as I moved here for secular work. So my current pattern has been to keep myself constantly aware of the "warnings to the rich and wealthy" passages of scripture. We have been able to increase giving. I have also been trying to increase our time serving a local church here. The church we are part of is also made up of international Christian's and not so much exclusive Chinese citizens.
On the missionary topic...I will just say that I have learned unless you are willing (& able with time) to be thoroughly educated in the culture and language you may do better supporting missionary efforts to train and provide resources to existing and new local pastors. So unless you feel the Lord calling you to be an international missionary, I will echo to serve your local church or maybe consider joining a smaller more rural faithful congregation in your area that may be struggling to keep the lights on and/or has a needs for male leadership as deacon or ruling elder. In other words, is their another smaller congregation that your family could potentially help revitalize by simply joining, loving, and serving. Also consider asking yourself are their neighbors you and your family could invest for time and resources as a means to show the love of Christ and hopefully see them come under the regular preaching of the Word & Sacraments. Also the ideas and encouragements to have more children and adoption are also terrific considerations. For adoption, I would speak with Christians who have done this before as it can come with it's own unique challenges.
The above are just some ideas I have been working through in my own life as I find myself financially blessed and with no bills. Also if you want to move, buy a home and rent the existing. Or if you like your existing home, you could buy another and rent that property out. Not as a primary means to get more wealth for yourself but to again set yourself up to continue to increase giving and supporting the Kingdom.
P.S. Correct me if I am wrong Ryan...but To Everyone: I believe Ryan does work a job already.