Red Lion is on the high street in Colchester but the entrance is in a walkway between the high st and a shopping area. Depending upon the time of day the walkway can be quiet but generally there is a fair amount of footfall but it would be easy to get into the hotel as there are also tea rooms, etc, there. From memory having visited someone there the reception is up a flight of stairs - I don't think there are any ground floor rooms ir.
However, it doesn't have a car park so you have to park in a pay&display with the closest being 5 minutes walk or you can use the taxi rank outside.