I would first suggest that you consider lodging near the Epcot resort area. Boardwalk, Yacht and Beach Club, as well as the Swan and Dolphin would be very close. All of these hotels would give you access to
Epcot via the International Gateway entrance which will put you right in the middle of World Showcase. You’ll enter between the United Kingdom and France pavilions. This entrance is especially useful as an exit after Illuminations to avoid the crowds heading for the buses, monorail and parking lot via the front of the park.
The above resorts provide transportation to Epcot via the Friendship Boat launches. This would be a restful way to reach the entrance.
For other resorts you will arrive Epcot via monorail or boat and if you are staying off-site, you could utilize the handicapped parking area with a permit.
Touring World Showcase can be tiring for anyone so you may want to split up your walk around the lake in to two days and/or take a mid-day rest back at your hotel.
I also suggest renting an
electric controlled vehicle (ECV) which are available at Epcot‘s entrances. (Note that availability of ECVs is not guaranteed though.) This would allow you to enjoy your experience without all the walking. I have a friend that utilized an ECV and was very thankful that he did. Friendship boats have ramps so that ECVs can drive aboard.
Consider renting an ECV from an outside company so that you may also use it from the park to your hotel, to tour the Boardwalk area for dining and shopping, etc. I have heard that renting from caremedicalequipment.com/ is very convenient as they deliver the ECV to your hotel. However I have not used them personally.
I hope this information will help make your journey around the World Showcase Lagoon simply delightful!