When as many as 3,000 costumed kids and parents from across the Treasure Valley converge on your neighborhood to trick-or-treat, you need to have a Halloween game plan.

Families who live along stately tree-lined Harrison Boulevard in Boise stockpile huge quantities of candy, some spending $300 or more. Many invite friends over for parties — and to help hand out treats.

“It’s an amazing, marvelous experience,” said Shelley Eichmann, who has lived on Harrison for more than six years.

Trick-or-treating on Harrison is a long-standing tradition. Eichmann said her father was among the children going door to door there in the 1930s.

One reason parents like the roughly one-mile stretch from Resseguie Street to Hill Road is because it has sidewalks and is well-lighted. Volunteer crossing guards and police add to the sense of safety.

But something has detracted from the fun in recent years: older freeloaders. Specifically, teenagers who can drive and even young adults are crashing the party and lining up to get candy.

“We have people with baby buggies and no babies in them. They’re collecting candy,” Eichmann said. “It’s a way to get free candy, and that’s not right.”

Eichmann said the problem was discussed by residents at a couple of neighborhood gatherings this fall. She wanted to get the word out that they welcome trick-or-treaters up to age 15 — but others shouldn’t expect to get treats.

“We have to restrict the age group because we have 25-year-olds and 32-year-olds who think we owe them candy,” Eichmann said.

Eichmann and her husband aren’t planning to check IDs, but they’re hoping that those old enough to vote won’t queue up for candy with the kiddies.

The prime time for trick-or-treating in the neighborhood is 6 p.m. to 8 p.m., and some residents would love it if people stuck to those hours. But doorbells sometimes begin ringing as early as 4:30 p.m. and don’t stop until 8:30 or 9.

Fred Willerup, who was adding pumpkins to his graveyard display Monday afternoon, said it’s an “honor and a duty” to be part of his neighborhood’s Halloween festivities.

Willerup said it doesn’t necessarily bother him if older teens show up for candy — as long as they’re wearing costumes. He said he was amused by a group of 18-year-old vampires who showed up at his family’s house one Halloween.

And if they show up in street clothes?

“It doesn’t ruin the night,” Willerup said. “The majority of kids are great and polite.”

Kathlyn Johans, who has lived in the neighborhood for 20 years, said she hasn’t noticed an influx of adults angling for candy. But she said there probably are more older teens because the overall number of revelers has grown over the years.

“We do get (older) people who come up and ask for candy. What are you going to do?” she said. “It’s pretty hard to filter out.”

She’s given college students candy, she said, and asked them not to return the next year.

Johans said that because of the crowds, she always has three people on her porch handing out candy from a large cauldron.

“A bunch of people come over, and we just rotate through,” she said.

Julie Ekedahl said all the friends she invites to her Harrison home bring bags of candy so the family has enough to hand out. She takes her own two kids to nearby 16th Street, where there aren’t candy lines outside all the houses.

That means her children get to ring doorbells, like she did as a kid, Ekedahl said.

Johans said she’s been impressed by the creativity of costumes she’s seen — including a baby dressed up as a chicken and carried in a KFC bucket.

When her family runs out of candy — all 3,000 pieces — they go inside and turn out the lights. Last year, that was at 8:45 p.m.

“We weren’t the first, and we weren’t the last,” Johans said.

Katy Moeller: 377-6413