i have both the 444 and the 45/70 in the marlin outfitter guide gun.i use only jacketed bullets,300 grn in the 444 with a velocity of 1900-1950.i have a scout style mount with an adco red dot on it.this is a wicked nice woods carbine.if you wanted something a little faster the 240 grn bullet would be a good choice.i would guess you could push this up to and over 2000 fps.
my 45/70 is a cast bullet gun,lower velocity heavier bullet.still a very respectable combination.not as flat a trajectory but cheap to shoot and great for close to medium range shots.you just need to make sure if you are going to shoot cast bullets you need a non-micro-groove barrel.the new hornady leverevalution ammo for the 45/70 is pretty nice,shoots good in the m-grooves.
with both rifles you ARE going to experience a fair amount of recoil.the 45/70 responds well to slower heavier bullet loads,if you are concerned about the recoil.a ported barrel although hard on the ears will help to decrease the amount of felt recoil.
my 444 is ported,my 45/70 is not,i o have a #1 45/70 that is magna-ported,it seems to help.
as far as accuracy it is hard to beat these marlins for lever gun accuracy.my 444 will shoot 3" or less at 100 yds,i do not have target sights,the adco is a hunting sight,put a 10 x scope on this gun i'm sure it would do better.the 45/70 is historically a target quality cartridge,you will not be dissapointed with the accuray you will acheive.my #1 with a 9x scope will put three touching at 100 using 405 grn cast bullets.i have not shot the 45/70 marlin for accuracy,the last one i had shot as well as my ruger.nothing wrong with 3 405 grn bullets into 1" at 100 yds.
overall i would say,want more speed,flatter trajectory go with the 444,want more versatility heavier bullets go 45/70.personally i couldn't decide so i have both.pick up two carbines one 444 one 45/70,i'll bet your wife wont'd be able to tell the diference between the two.good luck,adker