Name of children's book I read in the 70s?

I think you're remembering "The Swing in the Summerhouse" by Jane Langton. It's actually the second book in a series, all involving the same children. It was recently reprinted, but looks like it's out of print again already, though you can find used copies at http://www.amazon.com/exec/obidos/ASIN/0064401243/...

The titles in the series are

1 Diamond in the Window, The

2 Swing in the Summerhouse, The

3 Astonishing Stereoscope, The

4 Fledgling, The

5 Fragile Flag, The

6 Time Bike, The

7 Mysterious Circus, The

I think your other memory, of drawings coming to life, may be "Marianne Dreams" by Catherine Storr: http://www.amazon.com/exec/obidos/ASIN/0140302093/...

My area of the Mountain through Jean Craighead George Sam Gribley runs remote from his domicile in ny city interior the month of would. He leaves with only a penknife, a ball of cord, a hatchet, $40 he had saved promoting mag subscriptions, and a flint and metal set that he had offered at a chinese product proprietor's save interior the city. Sam receives a vacation with a guy utilising a truck north of ny in search for of his relatives's abandoned and overgrown farm interior the Catskill Mountains. He hikes to the Catskills and spends a lonely first nighttime in his small hemlock lean-to (a small tent-like structure that consists of a hemlock bough and a stump). He catches 5 trout, yet fails to commence a hearth to cook dinner them.... searching the Gribley farm, Sam establishes a living interior the stump of an titanic previous hemlock tree. He makes use of hand-awl and hearth to improve a organic hollow right into a house with area for a mattress, shops of amassed foodstuffs, or maybe a small hearth... Sam lives a free life interior the desert for more desirable than a three hundred and sixty 5 days jointly with his puppy, a peregrine falcon named Frightful, whom he had captured as a chick and hand-reared. His pals interior the wooded area contain the free-ranging musteline "Baron" Weasel, and a raccoon he names Jessie Coon James.... a lengthy time period after the unique novel became printed, George wrote 4 sequels: our area of the mountainOn the a concepts area of the Mountain (1991), Frightful's Mountain (1999), Frightful's Daughter (2002) and Frightful's Daughter Meets the Baron Weasel (2007). This looks to finish the sequels

Doesn't sound like The Secret Garden. If you don't have luck here, check with your local Children's Librarian.

The Secret Garden? Just guessing.

I believe you are refering to Bridge to Terrabithia. A boy and a girl used a swing to go to an island where they used their imagination to create a kingdom.