Prince George's County Council member James Herl said he had expected to spend his month-long summer recess "out in my backyard, with a phone hooked up, soaking up the sunshine."

But politicians' best-laid plans, like those of other mortals, have a way of going awry: Herl found himself indoors meeting with municipal leaders in his College Park-area district, seeking a compromise in a dispute over the route of the Green Line metro in the northern county.

The metro alignment dispute is just one of the concerns the council will face beginning tomorrow when the nine-member body reconvenes after its August recess. A handful of other issues, ranging from proposals to modify the county's strict property tax cap to efforts to repeal a tax break to the Washington Capitals hockey team, will occupy council members over the next few months as they near the first anniversary of their elections last November.

Among the bills expected on tomorrow's agenda is a measure proposed by member Anthony Cicoria that would modify TRIM, the charter-mandated freeze on property tax revenue. Cicoria's bill would become the first TRIM modification plan introduced this year, although union representatives for police officers, firefighters and deputy sheriffs have announced plans to draft their own measure.

Cicoria, a fiscal conservative who vigorously opposed a modification proposal that appeared on last year's ballot, said he has decided that the county needs more money. "We have to look at what's best for the future," he said.

Currently the county can collect only as much tax revenue as it received in 1979--about $143.9 million-- and critics have argued that the county has no way to pay for the services required by new construction. But modification proposals introduced in the past have twice failed to win the voters' approval.

Cicoria's measure, which he said he hopes to have completed in time to introduce tomorrow, would allow the county to add the tax revenue generated by new construction to the TRIM ceiling. If approved by the required six-vote majority of the council, the proposal would be presented to county voters a year from November.

Cicoria has also sponsored a handful of other revenue-raising measures to be introduced tomorrow. One bill would raise the tax on video and pinball games, from 5 percent to 7 percent, and another would raise from 1/2 percent to 7 percent the tax on refreshments served at performance halls or cabarets.

A third bill would impose civil fines ranging from $50 to $500 on violations of the county's housing code. Cicoria also plans to call for the creation of a task force to investigate other problems of county renters.

Tomorrow the council will also have to consider whether to override the first veto cast by County Executive Parris Glendening. Two weeks ago, Glendening vetoed a bill, narrowly passed by the council, that would have prohibited the use of county funds for school tuition for county employes, unless the money is specifically earmarked in the budget. Since the previous council consistently overrode each of former executive Lawrence Hogan's vetos, Herl said he views the vote as an important test of the current council's solidarity.

"The overriding issue is how the council is going to continue to work with the executive," he said.

After tomorrow's lengthy agenda, however, the council faces a number of other controversial issues. Over the next few months, the council must decide whether to confirm Glendening's nominee for police chief, Maj. Michael Flaherty, and whether to repeal a $1 million tax break granted to the Washington Capitals.

Last week Capitals owner Abe Pollin complied with the council's request to provide financial data on the team, but several council members interviewed said the data would make no difference, and said they would continue to press for repeal.

Eventually, the council is also expected to consider proposals to change two disputed metro routes along the long-awaited Green Line. Herl has proposed that a 600-foot tunnel be added to the so-called "E-route" that is to traverse his district on Calvert Road. But Glendening and Metro officials oppose that proposal as too expensive.

Council member Sue V. Mills has also vowed to continue her fight to force Metro officials to build the Green Line in the southern county--the "F-route"--toward the Branch Avenue terminus instead of the terminus at Rosecroft Raceway designated currently. Mills, whose efforts were rebuffed last year when two council members abstained, said she has waited eagerly for September to renew her efforts.

"Whatever it takes, I shall do," she vowed.