Eldon's is about a 12min walk from the port in Coxen Hole. We have walked there without any problems. When you walk out the main gates of the port area there will be a ton of men trying to sell you their tour or asking where you want to go, we just say no thank you and go on our way.
https://www.google.com/maps/dir/8F73%2B2W9+Berth+1+-+Port+of+Roatan,+Main+St,+Coxen+Hole,+Honduras/Eldon's+Supermarket/@16.3142949,-86.5443527,1145m/data=!3m2!1e3!4b1!4m14!4m13!1m5!1m1!1s0x8f69e87eb2e63ff7:0xa13205f66048929c!2m2!1d-86.5451279!2d16.3125362!1m5!1m1!1s0x8f69e880ee79b343:0x8766e61a32a9e908!2m2!1d-86.538659!2d16.3140781!3e2?entry=ttu