Your mission application provides many opportunities to add comments to a specific area of inquiry. Add extra information freely. The more the missionary committee knows about your situation, the better they can inform the general authority who will assign your mission call.
If you live within commuting distance of the Missionary Training Center, you can live at home and travel to and from the MTC each day. You will still need to pay for any meals you eat while at the training center, though.
In November 2011 General Conference, Elder Holland exclaimed, “We need thousands of more couples serving in the missions of the Church. Every mission president pleads for them. Everywhere they serve, our couples bring a maturity to the work that no number of 19-year-olds, however good they are, can provide.”
US cell phones are too expensive to use in foreign countries, so your mission office will often provide you with a local cell phone. The mission will not, however, provide you with a computer or with Internet access. 
Earlier this week Mormon Women Stand published an article I wrote that tells why I decided to write Senior Missions: What to Expect and How to Prepare. It’s called “Thinking of Serving a Senior Mission?”
You can read it here:
You can read the introduction to Senior Missions: What to Expect and How to Prepare right now:
https://marnaewilson.com/wp-content/uploads/2017/02/Senior-Missions-Introduction.pdf
