This depends on several factors. The inmate must be a long-timer with a lot of time left. They must be in a federal facility and the inmate must have a clean record while incarcerated. Please check with your inmate's case manager if it is even an option. 

no, there are no conjugal visits any longer

We don't think so... unless they are on Social Security disability (as those checks are on hold during incarceration)... maybe marriage 'unlocks' that hold?

the key is persistence. you should have your inmate talk to the chaplain to see if they are even eligible to get married in jail

some state and all federal prison's allow marriage, but it is reserved for inmates with lengthy sentences. if you are interested, have your inmate consult the Champlain at the compound for details.

Thanks for writing. Marriage can happen in few DOCs and the BOP. It is, however, a long process for approval. Our advice is to have your inmate contact the chaplain and tell them what he wants to do. If they'll consider it, your inmate will get a list from the chaplain that you'll have to handle on the outside. If his sentence isn't too long, I would seriously consider waiting to have a proper wedding on the outside because of all you're

You might be able to, but the prison rules for marriage are all different. We would suggest calling there and speaking to the chaplain.

sometimes, it depends on the facility... not every facility allows marriages so we would recommend that you contact the chaplain or the inmate's case manager to find out. 

Months and months if the petition is not contested. If it is contested, it'll take a long time

go with your gut, from experience, if you think something is wrong you are probably right