Another potential power source are all the power bricks floating around these days. Seems like everything you buy (cell phone chargers, etc.) comes with its own little AC/DC transformer. Thrift stores usually have bins of them. Find one with a 6V DC output..
Do you have access to the bulbs themselves? Got any pics? Any other info besides "6V" on the bulbs? (i.e., DC or AC ? What current rating?)
If you can determine some or all of that, it will narrow down your chances of not "letting the smoke out" when you apply the juice.
Having said all that, try a few AA batteries (4 @1.5 V should bring you to the 6V stated). Connect batteries in series (those cheap plastic battery holders are great, usually set up for x2 or x4 AA or AAA batts, and have a + and- terminal/wire, etc.) then connect the leads from one light to it and see what happens. If you get pos results, then add lights one by one...
And remember, everywhere - it's Ohm's Law...

Disclaimer: Although I am an engineer, I didn't stay in a Holiday Inn Express last night, so if you burn your place down, it's on you....
