Visiting Park Guell without booking/touring Monumental Zone

I believe the paid-entry part of the park includes a lot of the most distinctive features, but in truth, I didn't see the rest of the park, so I'm not sure.

You might consider going to the Sant Pau Modernista site instead. It's within walking distance of La Sagrada Familia, and as of last August one could walk right in. It's by the same architect who designed the Palau de la Musica Catalan, but the latter requires a timed tour ticket and might not be workable on the spur of the moment. Sant Pau is lovely. It's a multi-building site, so you'll be outdoors part of the time. Probably not something you want to do on a really rainy day.

You might also poke around on the Parc Guell website to see whether it would be possible to book your entry via a smartphone (assuming you have Wi-Fi or cellular access) as soon as you finish up with the church and are sure you're up for heading to parc Guell. Obviously, that would work only if mid- to late-afternoon tickets are still available. And I don't know whether you can do everything by phone or would need to have a way to print out the resulting tickets.

It is a green space. You can check it out on google street view or YouTube. The monumental is where the architecture is, but people lumpmit all together becausenitjis shorter to type. I agree Sant Pau Hospital is a hidden Modernista gem, close to Sagrada Familia and doesn't need prebooking....if you aren't overloaded by then.

Jane, I will also recommend the Sant Pau hospital visit, which is an easy 15 minute slightly-uphill walk from Sagrada Familia. It is a beautiful multi-building site, especially impressive since it was endowed specifically to be a hospital for Barcelona's poor population. I booked in advance the English language tour, which was a good way to see the facilities and ask questions. My group was very small, just a couple from Belgium and me, plus the guide. I also went to Park Guell first thing in the morning on my first full day in Barcelona. Went by Metro plus bus, then walked down into the center of town through the Gloria neighborhood. Park Guell is also a nice place to wander through, with its modern architectural feature, green space, etc.

The "Monumental area"- which accounts for roughly 7% of the park- contains most of the monuments but not all, a few can be seen in the free zone- and it's indeed worth visiting as well. Nevertheless, the reason for Park Güell "IS" the Monumental area.

For conservation reasons only 800 visitors per hour are allowed into this area and tickets are time-sensitive so visitors are expected to enter the area within the given time slots, hence the reason it's advisable to purchase online, otherwise if bought on the spot you might end up having to wait a long time for your assigned time-slot. As mentioned, there are a few things to be seen outside the Monumental area which might be of your interest, such as the Viaduct (http://brbun01.files.wordpress.com/2012/07/182.jpg) or the Turó de Les Tres Creus (http://static.panoramio.com/photos/large/49299751.jpg) at the top of the park and with an impressive view of the city: http://farm6.staticflickr.com/5450/8811907184_4a4bcffe44_o.jpg It's advisable to arrive a bit earlier to the park and venture to these sites.

More info: http://www.parkguell.cat

I concur with Enric. Actually I dare anyone not to.
A visit to Park Guell without entry to the monumental area will leave you disappointed.
If you are in the monumental area, then indeed, venture outside, it will give you an appreciation of the overall vision.