I was wondering about queuing at the various tourist sites, museums, etc to check my day pack (assuming all have cloak rooms). I have a reasonably small Pacsafe day pack and would prefer to keep it with me if I can...... How long are the queues generally to check and pick up from? Also, is it always a requirement to check a smaller sized pack? Thanks in anticipation.....

Most places will allow you to take them in - if they are day packs and not luggage size backpacks. Depending on the location, they may have to go through a security check.

How small is reasonably small, and how packed will this pack be?
Make sure to take it off your back and carry it on one shoulder. If it's not bigger than a large purse, you will most likely be able to take it in.

The lines at checkrooms at some museums varies. If it's a busy rainy or winter day, and people are also checking umbrealls coats etc, it will take a few minutes (maybe 10-15) , otherwise it's usually a minute or 2. And you generally get on the same line to pick up items as to leave them.

"The RoamSafe 100 is a lightweight, anti-theft backpack equipped with multiple security features. The RoamSafe 100 is ideal for short day trips, sightseeing and everyday use. Weight: 0.6kg Capacity: 15L Size: 28cm x 39cm x 15cm." I will probably be carrying bottled water, my digital camera, wallet, guide book, pen, tissues, sunglasses (unless wearing) and a few other odds & sods. Oh, and my very lightweight brolly.

It's small enough that you can carry it with you inside museums.

I think the only exception is Barnes Foundation just outside Philadelphia. you have to check everything before your visit, I believe.

Thanks yk and all - much appreciated