Hello, Kymberley!
This is a great question, because staying in a resort on the monorail line while in Walt Disney World really is the easiest way to go, especially if you plan to spend a lot of time in Magic Kingdom or would like to take the baby back for a nap back at your resort. However, there is a cost difference in doing so, so it's wise to really know if this is worth it for you.
That being said, we've stayed in several different locations with a baby in tow, and can also add that if you don't plan to park hop or if you don't necessarily need to head back to the resort, then back into the same park again, your transportation to Wilderness Lodge will not be too difficult either. In addition to the bus to Magic Kingdom, there is also a boat between the resort and the park. which makes traveling with baby in a stroller almost as easy as taking that stroller onto the monorail.
Take a look at your schedule and look for how many trips you'll have back and forth between the parks and your resort each day. If the thought of taking the baby out of the stroller and folding up the stroller each time you need to get to a resort via bus makes you wish you had booked on the monorail line, then your decision has been made. If, however, you see that Epcot is not on your schedule very often (and is the only easy transportation you'll be losing by staying at WL) then maybe this added expense isn't worth it after all.
In addition, so many Guests who've stayed at
Disney's Wilderness Lodge have become such fans of the property, they'll never stay anywhere else! There is so much to do, your six-year old is sure to absolutely love this resort!
Hope this helps! Please send more questions as you think of them! We love to help!