[A/S] wheel question

[SHMossLanding@xxxxxxx]

I need to replace the split rim type wheels on our 1965 Overlander.  My 
current tire size is 700R15.  The current wheels have a hole in the center 
where the hub fits through, and it measures about 3.5".  The lugs are 2.75" 
on center or what they call a 5.5" pattern.  Can I use a wheel with a larger 
center hole, if the lug pattern and the offset (0) is the same?  And as long 
as I have your attention,  any suggestions as to replacing the tires with a 
more current size.  The 700R15 seems to be a bit unusal.

                                                     Thanks,
                                                       Chuck & Lynn
                                                       1965 Overlander