Frankfurt sights and hotels

Do you recommend this?

Yes, I always stay at/near the ariport when traveling out of FRA in the morning.

You have the Marriott/Sheraton directly attached to Terminal 1. And the Hitlon Garden Inn which is attached to the train station, which is also attached to Terminal 1. It's just a longer walk by about 10 minutes. I have used this Marriott for over 25 years, both for business and when vacationing with my wife.

You also have many less expensive options in Gateway Gardens, a relative new business development with at least a half dozen hotels. I use the Moxy when traveling solo and departing out of Terminal 2. It is a 15 minute walk to Terminal 2 or a very short ride (no free shuttle) to either Terminal 1 or 2.

Both options have an S-Bahn stop to get into Frankfurt. Also, if comming by train there is a station at the airport and you may be able to travel direclty to the airport without a connection at the Frankfurt Hbf. There are lockers at the Hbf it you plan to travel there and then sightsee before going to your hotel.

How should we spend our day?

I suggest you search on this site for Frankfurt. Your's is a frequest question and there have been many posts in response.

How should we spend our day?

How shall somebody recommend without knowing your interests?

Ah, yes, what we like would be helpful. I like the old part of cities. I like visiting churches and such. My husband may be tired these activities. Probably would not want to visit another museum unless it was to see something specific.

I would stay at the airport if you have an early morning flight. Staying at Gateway gardens takes almost as much time to get to the airport as staying in the city, either from waiting on a train or traffic on the autobahn.
Hilton Garden Inn, Hilton, or Marriott/Sheraton.

Frankfurt has several medieval churches, the Kaiserdom, St. Leonhards, the Alte Nikolai, and Deutsche Orden.
The new Alt Stadt is popular and very well done.
If Jewish heritage sites are of interest, Frankfurt has probably more than any other city in Germany. The Judengasse Museum is built over the cellars of the medieval Jewish Ghetto, making it rather unique.
Depending on the day of the week, there are some great Farmers markets in the city as well as the indoor market, the Kleinmarkthalle.

if you want a really old church, head to the neighborhood of Höchst, where the Justinus church is. Consecrated in 830 and still original with a few additions over the centuries. Lots of half-timbered houses here and a small palace, plus a Farmers market on Tues. Fri. and Sat. from 7-1300. Great food on the plaza overlooking the toll gate and palace.

Will you be here over Easter weekend? The Pealing of the Bells is happening the day before Easter.

We'll be there April 22, right after Easter. I appreciate the help you have all given. Thank you.

I enjoyed a walking tour through the old part of town. Check it out:

https://frankfurtonfoot.com/tours

I second the suggestion of the tour offered by Frankfurt on Foot.

I third the suggestion of a Frankfurt on Foot walking tour.

I'm late to the game, but I fourth the suggestion.