Rhine River and Mosselle River

Yes, there are frequent cruise boats. http://www.kdrhine.com/rhineschedule.htm

I assume that was a spell-check fluke. Baccarat is a casino card game. Bacharach is one of the towns on the Rhine.

The same question applies on the Mosselle River. I'd like to visit some wineries (cruise might be better than driving if we are drinking). Any suggestions?

There are quite few locks on the Mosel river which makes cruise boats problematic. Very slow going. Better is to use the rail line along the river. You can get a VRM group day ticket for 22.15 EUR and gives unlimited use of the regional trains along the Mosel as well as both sides of the Rhine after 9 am week days, all day week ends.
Trains run every hour both directions along the Mosel. Back in the day, it had the nickname as (in German dialect) "The Little Boozers Line" because wine makers used to bring their wares to the local stations and do whistle-stop wine tastings through the open windows of the train. Don't expect that now days, but each town has its own wine brand plastered on the hillside "Hollywood" style.

To cruise the river, take the train south to Bingen, board a boat there, and cruise north to either St. Goar (1.5 hrs.) or Boppard (2.3 hrs.) (Don't cruise from north to south, or the same trip takes twice as long - the current is very strong.) Also, don't pay good money to cruise to/from Koblenz... the scenery near Koblenz is lacking. When you finish the cruise in St. Goar or Boppard, just take the train back to Koblenz. The Rhineland-Palatinate ticket day pass will get 2 adults to Bingen and back to Koblenz by train for E29.

There are 5 KD boats per day that cover this trip. The boat schedules are somewhat irregular, so hopping off and on is not very convenient. Do your hopping on and off by train instead on your way to Bingen - trains run every hour in each direction - then take a late afternoon boat north. Boppard, St. Goar, Oberwesel, and Bacharach are all worthwhile. But be sure to start your cruise in Bingen for the best cruise scenery. Show your train ticket at the Bingen dock for a 20% cruise discount. Then the cruise ticket will cost about E16 to St.Goar, a little more to Boppard.

Thanks for the information and I fixed the spelling error (which was a spell check issue - but I am pretty sure that my initial spelling was wrong too!).

Are there multi-day train ticket packages (since we will likely go up the Rhine one day and the Mosselle the next)?

There are are multi-day TICKETS that you can buy, like the 3-day VRM pass. It's good only within the light-green VRM zone you see on this map: http://www.vrminfo.de/fileadmin/data/pdf/2015/Schienennetzplan.pdf
On this ticket you can travel south to Oberwesel on the Rhine, and west to Bullay on the Mosel. The price for one person is €37.60. It can be used at any hour of the day.

A one-day VRM pass for the same area for 2-5 passengers is good after 9 am weekdays (anytime on Sa or Su) and costs €22.10

VRM Price table: http://www.vrminfo.de/fileadmin/user_upload/Preistafel_2017.pdf

For a train ride further south along the Rhine to Bacharach, Bingen, Mainz, etc. - and further along the Mosel to Trier and beyond - there is no multi-day pass; you need the Rhineland-Palatinate day pass (€29/2) I linked to previously. THIS map shows you the area of validity (much larger than the VRM zone.)

Do not buy these tickets online in advance - they are not refundable if you change your mind. You CAN buy them from the station on the day of departure (or the day before if that's more convenient - just be sure to enter the correct travel date.) They do not sell out. Ticket machines have an English-language screen option.