Europe introduction for a 10 yr old!

Janet, What a wonderful idea. A 10-year-old should be just old enough to understand the geography and what he is seeing.

I would suggest an open-jaw, fly into London, out of Paris and take the train (Eurostar) in between. Compare and contrast two world cities. They look very different, language, food, climate, Windsor vs Versailles, the tube vs the métro, and with a 190MPH train ride in between.
Try to do this earlier in the year, May/June instead of August. August is hot and crowded and more expensive. But I assume you are constrained by school holidays.

That plan would however make it difficult to fit in Ireland as well within your budget and time constraint. You could do Ireland after Paris. But, as I think you probably want to see the Irish countryside that would involve a car and a number of days.

How long is the total trip going to be? If it's just one week, I would go with what the boy really wants to do. Ireland is a perfect introduction to Europe. The Irish are very friendly and love kids, they're even allowed in the pubs until 9:00 pm or so. There's castles to explore and lots of outdoor places to visit and fun things to do.

If you just have the week, go to Ireland as there is plenty to keep you both interested for that time. There won't be any language barriers. Well, only the local accent, which can be difficult to follow! What interests him about Ireland?

Dublin isn't cheap, but you have plenty of time to plan and book the best value accommodation. You could have a few days in somewhere such as Cork as a contrast to Dublin.

There are lots of great places to visit, but you haven't given much indication of your interests.

If on a budget, avoid Switzerland, Italy and Scandinavia.

Is the $5,000 CAD budget supposed to cover airfare for you and your son in addition to lodging, food, sightseeing and local transportation (e.g., buses, trains, car rental, etc.)? Or is that your budget after you finish paying for airfare?

Although London can be pretty pricey, you still can do some things on a budget if you plan carefully. There are a decent number of sights and museums that don't charge admission, but some places a 10 year old might really want to go to in England (e.g., Harry Potter set tours, etc.) can be really expensive.

Lodging can be very expensive in London, so start looking at options early. August is a popular month for the locals to take their vacations, so sometimes you can score good deals for lodging at some of the budget class business hotels (e.g., Ibis), you can also look at options for hostels, BnBs, university housing (local colleges and universities rent out dorm rooms to travelers hat are sitting empty during the summer), and apartment rentals (VRBO, Airbnb, etc.).

Ireland is a great place for a trip with a 10 year old. Although it's great if you can afford to have a rental car to explore areas outside of the major cities, you can still manage to craft a trip of 7-10 days using public transportation if you base yourself out of some of the cities and just do some day tours. Ex. you could spend 3-4 nights in Dublin and tack on a day tour outside of Dublin, train to Galway and base yourself from there for a few nights to do day tours to places like The Burren, Connemara, Cliffs of Moher. You can also catch a ferry over to the Aran Islands and spend a night on the Island and tour around by bike, minivan or pony & trap rides. That's easily a week long trip right there without the expense of renting a car - or you have the option to just rent a car for a day here and there to get outside of the city.

The Netherlands and Belgium are also good countries for a 7-10 day trip. Easy to get around by trains and nice opportunities to do things outdoors. Both are pretty English friendly which can be helpful if your son is presented with an opportunity to spend time around kids his age in a park or other outdoor venue.

"I would go with what the boy really wants to do."

That's my advice as well (tempered, of course, by time constraints, safety issues, budget, etc). If you take him someone because it's what he should want rather than what he does want, it will just make him miserable. He has many years to go back to Europe and see other places. So, if he wants Ireland at this time, do what you can to make that happen.

Ireland has the further advantage of not being nearly as hot as many other European destinations; I don't know if it ever gets hot enough to want air conditioning. Reports here indicate that London can, and that while such days are not too common, thanks to climate change they are more common than before. Places with A/C may raise your expenses, so if you want it, you need to budget for this.

Is your son 10 now or will be 10 in Aug 2018?

Kids can be fickle and by March he could have changed his mind on where he want to go how many times?

Of course you know him best. Why/how did he choose Ireland?

Giving kids a chance to give input is good, but planning a trip 13 months ahead on a youngsters possible short term whim, does have some hazards.

As others have said, if your son wants to see Ireland, a one week trip for the 2 of you would be an excellent idea to introduce him to overseas travel. The flight travel time between Toronto and Dublin would be slightly shorter than to London or Europe which may help with your budget and the time change. Plenty of things to see and do, and what urban 10-year old wouldn't enjoy the chance to visit a few castles or spend some time at the seaside? If you need family travel ideas, have a look at irishtourism.com or http://www.minitime.com/trip-tips/A-Familys-Guide-to-Dublin-Ireland-article

I agree with taking him to where he wants to go - Ireland! It's perfect for a week long trip.
We have traveled with our son quite extensively and always included him in planning. We go over guidebooks together and we all pick out places we want to see. It gave him ownership of the trip and ensured that he was engaged and having as good a time as we were. Your son is definitely old enough to help you plan and he'll have fun doing it!
To make your money go as far as you need it to consider staying at airbnbs...we often stay in rooms in people's homes which I absolutely love doing! You get to know a local person or family, they can point you in the right direction of great places to eat and visit, and it can be very inexpensive. Maybe look for some on farms? That might be really fun for your son!

I just want to second the AirBnB recommendation, as well as looking into local rental website. I don't know about Ireland, but Germany has several within-Germany spare-room-rental website, and they're all cheaper than AirBnB AND you work directly with the owner rather than through the website. Our 3-week accommodation spending will right at $1000 USD for 4 people! I think you can totally do a week for $5K CAD, especially if you get outside the ultra-huge cities.

What a great plan you've got coming together! Stay as flexible as you are right now, and be willing to just have a chill-out day in between big sight-seeing days. That was my hardest lesson traveling alone with a 2 and a 5 year old in China for 2 weeks. :-) This year in Europe, we will have many more chill-out days!

Thank you all for the great replies and ideas! I love the London/Paris idea, but and I am now feeling more comfortable with Ireland. I just thought Ireland should be more of a "drive yourself" holiday and I really wasn't good with that! 5k is our TOTAL budget including airfare, so a bus tour won't fit. Son will be 11 on the trip and he just has an interest in Ireland as we are part Irish and he has an online friend that is Irish and he loves him. Castles are a must and we also want to enjoy a little of the pub culture :) Food shouldn't be too expensive as restaurant dining will be limited. Son prefers his food fast, so I see a lot of take out, pizza and picnics on this trip. I'm okay with that;)

Since he really wants to see Ireland, is part Irish, has an Irish friend, and you've never been, my suggestion would be Ireland for those and a number of other reasons. There isn't a language barrier, there is a wide variety of things to see and do, and you should be able to do it on your budget. This will be a perfect opportunity to get him involved the in the planning process with regard to where to go and what to do. The more he is involved, the more "ownership" he'll have of the trip, and the more he'll enjoy it. That enjoyment should then whet his appetite for other travels. You mentioned being single. I hope I'm not bringing up something unpleasant, but if there is an ex spouse, you need to find out what is required to take him out of the country.

If you don't want to drive you can consider using blablacar. It's a ridesharing service but not like Uber and Lyft...people who are going from one location to another post that they have empty seats in their car and will let you ride along for a small charge. It's fairly common in Europe and lots of people use it. Another option is the Bus Eireann...a local company that shuttles between most everywhere in Ireland. Cheaper and more relaxing than renting a car! I love buses in Europe - Ireland is small enough that any one ride won't be too long.

August is a good month for Ireland. It rarely gets really hot there and will probably rain a little less than other parts of the year - still pack a good waterproof rainshell and a sweater to layer under it.

To save money, reduce your packing to small carry ons and fly Toronto to Dublin or Cork on WowAir (discount airline that goes through Iceland). I've flown them the last couple times to Paris for under $600 round trip (last one was $500).

Dublin is a crowded city, there are some great sights but it's not the best of Ireland. The real fun is to get out into the small towns, see historic sights, listen to traditional music and just meet locals. Children are welcome in pubs until about 9 and it's almost impossible to avoid conversations with friendly people.

I'm most concerned with how you will get around? Rental car is the best option. Once Irish roads were notoriously bad. Those days are gone but there are still a lot of very narrow roads. If you are comfortable driving, that's your best bet. The other option is to limit your stops and use the buses - another great way to save money.