The 27-year-old missed both legs of the semi-final win over Rochdale because of an ankle problem, but scans have shown no lasting damage, meaning he is pushing for involvement at Wembley.
Miller has made 40 appearances this season but the second half of the final game of the regular season - also at Rochdale - is the only action he has seen since Easter Monday.
But he told KentNews: "Thankfully the last scan I had was good news. It was fluid round the ankle but the main thing was it didn't show any fractures or muscle tears. It's been knocking round since the Brentford game four or five weeks ago. It's just been frustrating because I've not been able to train consistently.
"The boys had a couple of days on Monday and Tuesday off but I met Dan (Ellis, fitness coach) who put me through my paces. I got a lot out of it and I feel good. I'm fit in all aspects now and I'm ready to go, it's just up to the gaffer (Mark Stimson) now.
"I watched the first leg on television and you just feel a million miles away from it all. It's not good for me. Obviously I watched the boys at home. It was like a carnival atmosphere and something you want to be involved in. Being involved throughout the season and missing out on games like that it does cut deep. It's horrible watching games like that."