In 1820 and 1821 more than 3,000 emigrants boarded ships for this journey. Though the accommodations varied slightly, none of this was Carnival Cruise. Here is a description, published in 1826, of the 1821 voyage of the David of London. [This is a link to another website - use your "back" button to return.] The passengers from the David of London rendezvoused with passengers from the Earl of Buckinghamshire to complete the trip to Lanark - and those passengers included Peter's brother John McLaren, his wife Margaret (Stirling), and their four children.
Keep in mind that Peter McLaren was forty one years old at the start of his voyage, and his wife, Janet (Headrick) was forty two; their children, four girls and three boys, ranged in age from ten months (youngest daughter, Christina) to fifteen years (eldest daughter, Isabella). Brother John was forty six during his voyage, his wife, Margaret Stirling was forty one; their children, three boys and a girl, ranged in age from two (son Peter) to twenty one (oldest son Findlay). Now look at another description of life aboard one of these ships: An 1828 Voyage [This is a link to another website - use your "back" button to return.] and consider what this must have been like.